Back when I was in Yeshiva, we were allowed to relax and let off steam by playing basketball, baseball, football (I was in a cold climate, so football in the snow was a favorite) listened to the occasional game or bob grant on the radio. Now, these pastimes are considered treif, (a side affliction of this is that a good bachur would almost never be caught dead in a non learning camp, despite the fact that the good bachurim are needed as proper role models for the younger boys in camp, and they are only available bein hazmanim – rabbi bender shlita has mentioned this in the past, but noone, except parents of boys in camp, realize just how serious this is) but, young men still need to let off steam and relax, and being the good guys they are, are not sneaking off to bars, and drinking beer has become the means to let off steam and relax.
As the father of a number of young men “in the dorm”, I trust their judgement that they wont do anything stupid, but, young men being young men, it is inevitable that some do. As a parent, proper chinuch, followed up by tefilla, and more tefilla, is what keeps me from worrying all day, every day.