Attending a few gatherings of completion of Hadith books (like the khatm Bukhari) for the purpose of barakah etc is applaudable and encouraged.
However, the recent trend of arranging public ‘maqra-ahs’ (also called Hadith Majlis; swift Hadith recitals) of Hadith books, like Sahih Bukhari etc. are indeed beneficial for the scholars, but harmful for the layman who doesn’t have a sound grounding in the basic subjects of the Islamic sciences. Such recitals should be held in controlled environments, for the scholarly only. An ‘under qualified’ layman cannot suffice on mere Hadith recitals like these after which ‘ijazah’ (permission) for transmitting Hadith is given to all. This could inflate one’s ego more than his knowledge!
(see similar warnings in Muqaddimah Ibnus Salah, pg.250)
My Esteemed teacher, Al-Muhaddith Shaykh Muhammad ‘Awwamah (may Allah protect him) has discussed this in his recent book; ‘Ma’alim Irshadiyyah’.
Here under is an explanatory translation of that section in the book :
A discussion regarding the innovative methods that have been introduced in the swift recitals of Hadith books
The debate regarding contemporary styles of teaching, calls me to discuss these new methods which have been introduced in the [swift] recital of the books of the Prophetic Sunnah.
Very concisely I present the following:
Firstly, a quick comparison between incidents pertaining to recitation and listening of Hadith books, in the past and that of current times, gives us a true unbiased ruling over the recent intrusions on the traditional scene.
Eye opening incidents from History
From among the incidents of the predecessors in precision of receiving and narrating Hadith are the following:
1) It is reported concerning the reliable, upright scholar; Ali ibn Hasan ibn Shaqiq al-Marwazi, one of the exclusive students of Ibnul-Mubarak (rahimahumallah), that he was asked: “have you heard ‘the book of prayer’ from Abu Hamzah (As-Sukkari)?”
He replied: “I heard the entire book, but one day [whilst reciting], a donkey brayed resulting in me not hearing one Hadith or a portion of a Hadith. Thereafter, I forgot which Hadith of the book it was, so I left the entire book!”
2) Ibn Ma’in said: “We brought some Hadiths of ‘Ubaydullah ibn ‘Umar to Hatim ibn Ismail (rahimahumullah). After he had recited to us one Hadith, he said: “I ask Allah’s forgiveness! I had written a book [of narrations which I had heard] from ‘Ubaydullah, but then I had doubt regarding one particular Hadith, therefore I will not narrate anything from him.”
3) Yusuf ibn Muslim (rahimahullah) said: “I heard al-Haytham ibn Jamil (al-Baghdadi al-Antaki) saying: “I heard seven hundred Hadiths from Shu’bah (rahimahullah), but I then developed a doubt regarding one Hadith, so I left all of them.”
4) As-Sam’ani quotes the following narration from Imam Yahya ibn Yahya at-Tamimi an-Naysaburi, one of the narrators of al-Muwatta from Imam Malik (rahimahumullah): “After having completed the reading of al-Muwatta, Yahya said to Malik: “my heart is not at ease with this listening. Imam Malik asked: “Why is that?” he replied: “It is because I fear that I may have omitted something [during my recital].” So Imam Malik recited the entire book to him. When he had completed the reading Yahya said: “My heart is not pleased with this either, because I fear that something may have escaped my ears.” Imam Malik asked: “So what do you propose?” he replied: “I will read it again and you will listen.” He then recited, thereby achieving three readings of the Muwatta.”
5) Hafiz Ibn Hajar (rahimahullah) states at the end of the biography of Imam al-Hafiz Abu Qurrah az-Zabidi: “He compiled the book as–Sunan according to the chapters (of jurisprudence) in a single volume, which I have personally seen. A distinct habit in this book is the he does not say in his narration of Hadith: ‘So and so narrated to us’ (حدثنا فلان) [like is the norm]. Rather, he only says: ‘So and so mentioned’ (ذكرفلان). When Imam Daraqutni (rahimahullah) was asked about this he said: “An irregularity had befallen his books; therefore he was cautious of being explicit with the usage of the term: “So and so narrated to us” .  (حدثنا فلان)
6) Az-Zarkashi states that Shaykh Abu Muhammad al-Juwayni narrates from Abu Bakr al-Hiri about Abul-Abbas al-Asam (rahimahumullah): “A Hadith was being read to him, and he said: “I can narrate half of it, and not the other half.” When he was asked about that, he replied: “I read half of it to the shaykh thereafter a donkey brayed, so I did not know: if the shaykh heard the rest or not? Because of this doubt, I left it. This is how [cautious] the people were”.” 
The demise of this Abul-Abbas was in the year 346 A.H. Look attentively and comprehend his statement: “This is how [cautious] the people were”!!
The incidents which I have quoted above clearly attest to the people [of the past] being like this.
7) It is mentioned, in the biography of Imam ‘Ibnul-Imam’; Abu ‘Abdillah Muhammad ibn Fadl al-Furawi (rahimahullah) that he said: “We would hear the book ‘Al–Musnad’ of Abu ‘Awanah being read to Abul-Qasim al-Qushayri. A very modest man would be present sitting next to the Shaykh (al-Qushayri). My father was the one reciting. It so happened that after he had recited a substantial portion of the book that modest man was absent one day. The Shaykh came out, according to his habit; he would generally come out and take his seat. At this time he was wearing a coarse black upper garment and a small turban. I was under the impression that my father had been reciting the book to that modest man [who was now absent]. Suddenly my father began reciting, so I said: “My Master! To whom are you reciting? The Shaykh is not present.” He asked; “It is as if you think my Shaykh is that (well-mannered) individual?” I replied: “Yes.” He became annoyed and uttered: “inna li-llahi wa inna ilaihi raji’un.” Addressing me, he said: “Oh my beloved son, your Shaykh is this man seated here.” He highlighted that spot in the book and thereafter repeated his recital –for my sake-from the beginning of the book till that spot.”
This narration also shows the importance of knowing the identity of the Shaykh under whom one is studying.
8) Imam al-Hafiz al-Qutb al-Halabi (rahimahullah) says in the biography of Imam Ibn Daqiqil-‘Eid (rahimahullah): “He was a paragon of caution and precision. I brought him a juz (booklet of Hadith dealing with one section out of the various sections of the sunnah)which he had heard from Ibn Rawaj and which he had written himself. He said: “[Just wait] until I study it.” When I returned to him and he said: “This is indeed my handwriting, but I can’t remember hearing it” so he did not narrate it [to me].”
These incidents, and others besides them, present an accurate image of how recitation and listening [to Hadith] would occur in the past. They illustrate that the transmission of chains was actually considered part of religion, and is a glorious trait of the Islamic sciences, in addition to it being a manifestation of Islamic ingenuity. It also proves it to be a source of contentment and dependence on to the religion of Islam. [i.e, when one reads incidents like the above, one becomes convinced of the divine protection of the knowledge of Islam, thereby rendering it totally reliable.]
With the passage of time
A second point to understand here is: as time passed, two matters began to intrude into the system of acquiring Hadith;
The first being: the habit of bringing tender aged children to the gatherings of narration, as well as those who were not scholars.[They did this with the expectation of such attendees progressing in Hadith, later in their life]
Second was the desire of some scholars to acquire shorter chains of narrations for particular books or to achieve more chains for that book.[which they had already studied diligently prior to that]
As for the first group
On many occasions the hope for this child would materialise, and he grows up dedicating himself to knowledge and will be in the future, a scholar who is sought by travel due to his knowledge and short chain of narrators.[Since he attended lessons of seniors as a child, his chain would be shorter than his fellow contemporaries]
Likewise, it is possible that the other person who was not from amongst the scholars also applies himself, and becomes blessed by treading the path of knowledge and thus he becomes from the scholars too. Such examples are many.
Frequently though, neither this nor that occurs…
The ill-effects of the unqualified attending such gatherings
From among the ill-effects of the presence of these two categories of people in these gatherings, is that they end up narrating what they had acquired at a time when their aptitude for acquiring Hadith was lacking.
During this early period in their lives, they may have acquired some renowned book too. Despite their acquisition of that book being deficient, it would not be harmful to that celebrated book which is already in circulation [due the prevalence of other reliable reporters/copies of these books]
However, they would have also acquired booklets of Hadith that are called: juz. [a booklet of Hadith dealing with one section out of the various sections of the sunnah] This juz could be unknown and not in circulation. Since both these types of learners were not suitable to receive Hadith as it should, the possibility of them lacking accuracy and proficiency in what they have received is very likely. It therefore becomes difficult for the scholars coming after them to pass verdicts of authenticity on the Hadiths of these ajza. [plural of juz].
As for the second group
They have, in reality already acquired that book on numerous occasions while adhering to the highest forms of caution and precision, in addition to studying the meanings of the Hadiths contained therein.
Now they pursue another recital of that book out of desire to increase their number of chains for that book and so that their chain of narrators be elevated. Their acquiring by this manner will not harm it, in the least, if anything comes to pass.
A Contemporary Trend
On the other hand if this feeble acquisition [like that of the first group, which has become common nowadays!] is the first and last acquisition of that book of Hadith, and by means of it this person begins to boast that he heard such and such a book from the six famous works, whilst not having any previous knowledge regarding the established principles of knowledge: then there is no value to this listening and acquisition!
The following is just one of a multitude of contemporary stories about recitals of Hadith books:
Once, more than forty years ago, a student came to me giving an account, like a proud peacock. He said that he had studied such and such a book, of the six famous works, under the tutelage of so and so shaykh (who was a famed scholar). He continued listing various works and scholars, until he mentioned “Sunan Tirmidhi”, which he claimed to have studied under a very eminent scholar. So I deliberately asked him: “Without any gap!” (بلا فوت؟) He immediately kept quiet and didn’t understand what I had just said!
So I ask the reader: is this the type of transmission that Imam Ibnul Mubarak (rahimahullah) referred to when he said: “The transmission of Tradition with a chain is part of religion”?! (الإسناد من الدين)
May Allah save us from that! (معاذ الله من ذلك)
What he actually meant was the likes of what I just cited a little earlier, about his student Ali ibn Hasan ibn Shaqiq.
A Grave Misinterpretation
It is as if the propagandists who promote this method are unmindful of the following two aspects:
Firstly; they are oblivious to the difference which I have already explained, which is:
The earlier scholars first acquired those books, with absolute precision and mastery as well as one could possibly wish, thereafter they acquired them in this manner for a specific motive. Therefore, the argument of the careless ones who quote these examples as evidence is what is termed by the Theologians (usuliyyun) as “analogy with a disparity” or “incorrect analogy”. (قياس مع الفارق / قياس فاسد) 
Aiding the Enemy
Secondly; they are unmindful of the current situation we find ourselves in; wherein numerous denominations are attacking the Prophetic Traditions, trying to raze its being an authoritative source from the hearts of people!
These factions include: those who view only the Quran as an authoritative source, the laymen, rationalists and the ignorant who feign having knowledge. They employ these fragile methods of acquiring Hadith as a pretext to contest the Prophetic Tradition, saying: “If the Traditions of your Prophet (sallallahu’alayhi wasallam) are based on this kind of a foundation, then it is a foundation on an abyss which is about to collapse and fall apart”. [i.e, unreliable]
All of the above shows the need to fully comprehend the affairs, understand the occurrences and suitably apply what we read according to the current circumstance we live in.
[May Allah Ta’ala grant us the true understanding of the all of the above, and may He bless the sincere ones with the tawfiq of accepting the truth. Amin]
Download the above as an e-book here
 pgs.188-194.  From here on, all subheadings are added by the translator. This is to create ease for the reader to follow the various angles of the discussion.  al-Kifayah, 234-235  al-Kifayah, 234-235  al-Kifayah, 234-235  Adabul Imla, number:22  Tahdhibut Tahdhib, vol.10, pg.350  Nukatuz Zarkashi, vol.3, pg.1008
 Siyar A’lamin Nubala, vol.19 pg.618 & Tabaqatush Shafi’iyyah, vol.6 pg.168  There are many contemporaries who have attended Maqra-ahs repeatedly, thereby achieving several acquisitions of some books. Of these, some are such that not a single acquisition of theirs was done with adequate commentary of the Hadiths. These will remain in the same category being discussed by my Respected Shaykh above.  This is an important disclaimer from my Respected Shaykh (may Allah protect him).
This entire expose is to explain the harms of this kind of (unqualified) people attending such Hadith recitals. The learned and scholarly who are adequately equipped in the fields of Islamic sciences are the real deserving ones for such Maqra-ahs. Ibnus Salah (rahimahullah) says: ‘One who merely seeks to increase his number of Shuyukh (plural of shaykh) and thereby attain fame, has wasted his time and is deprived of tawfiq (divine ability).’ (Muqaddimah Ibnus Salah, pg. 249)  See incident (1) under the subheading: Eye opening incidents from History.  It’s a common contemporary wrong, that we justify our misdeeds with the justifiable ones of the salaf (pious predecessors)
Ibnul Jawzi (rahimahullah) writes in ‘Talbis Iblis’, pg.155: “One group of those who aspire to amass abundant chains, are sincere, but shaytan has occupied them with this so they do not engage in what is more beneficial for them. If they argue that many of the Salaf also amassed [a large number of] chains, like Yahya ibn Ma’in, ‘Ali ibn Madini, Bukhari & Muslim (rahimahumullah), then the answer to that would be: These [Muhaddithun] had been able to do both; acquire the other necessary branches, like fiqh etc in addition to their achievements in Hadith… Very few are capable of such a combination in our era.” Ibnul Jawzi’s demise was in 596 A.H.!! End of quote from the book: Ma’alim Irshadiyyah.