This is going to be a departure from the usual posts in this thread, as it will actually site sifrei halacha instead of “internet Torah” quoting various seforim or “boych svaros”.
There is usually an issur to be mevatel one’s daas, and the mitzvah of drinking by the sudas Purim is the exception to the rule. The mitzvah of drinking is connected with the seudah, and there is no mitzvah of seudah at night (OC and MB 695).
The Mishna Brurah (THE poseik for those in yeshivish circles, not the obscure seforim quoted as the heter) says (based on the Pri MeGadim) that the shita of the Rem”a is “raui laasos”- i.e, that is the PROPER shita to follow, NOT the shita of getting completely stoned. Therefore, giving alcohol to a yeshiva bochur is a VIOLATION of the halacha he should be following, even if it’s in the daytime, even forgetting about the secular laws of giving alcohol to minors. At night, of course, when there is no mitvah, it’s as assur as it always is to drink. The Shaarei Teshuva brings down that those who come to improper behavior should NOT drink more than usual, and quotes the gemara of Rabbi Yehuda bar Ilai who only drank on Pesach, meaning he never drank on Purim. So a real yeshiva bochur trying to fulfill the mitzvah as properly as possible will be following the Rem”a, NOT the other shitos.
The Beis yosef furthermore says (Brought down in Aruch Hashulchan 695) that drinking so much is ASSUR. If a bochur wants to drink that much, he is oveir an aveirah. So claiming a bochur who wants to reach shichruso shel Lot is being mekayem a mitzvah is wrong, as according to many mainstream poskim he is doing an aveirah. The Aruch Hashulchan holds the mitzvah is to drink, and drinking more than little bit is a reshus, whereas it’s usually assur. So if a yeshiva bochur comes to my house at night asking for alcohol, I tell him there is no mitzvah to drink at night, so it’s an aveirah. In the daytime, I say that the mitzvah is at the seudah. And at the seudah, I quote the mishna brurah. So Volvie, when should you give a bochur alcohol, even if there’s no sakanah problem (which there unfortunately is today)?
Bottom line for litvish yeshiva bochurim, and you can confirm it with the Mishna Brurah and the Aruch Hashulchan, along with Rav Shmuel Kaminetzky Shlit”a:
There IS a mitzvah to drink on Purim. The is, according to many poskim (among them the Beis Yosef), an AVEIRAH to drink to shichruso shel lot, as this leads to many aveiros. According to the Aruch Hashulchan, it’s a reshus to drink to that point, but the mitzvah is just a little bit. According to the Pri Megadim, who is seconded by the Mishna Brurah, the Rema’a method is the PREFERRED way. Finally, there is no mitzvah to drink at night. So by not giving a bochur alcohol, you are being MACHMIR on halacha, not meikel on halacha, even forgetting about chamira sakanta mei’issura.Volvie’s “common understanding of ad delo yada” has as much halachic standing as the common misconception that shalach manos needs to have 2 brachos. A little bit of light chases away much darkness.