My problem lies that it happens more than just once on the weekends. As a former college athlete I completely understand where you are coming from QUIK, but the problem is that people just cant tell when its too much.
Have they been educated on the ill effects alcohol has on recovery? On top of that if they are drinking they are probably staying up late (going out) and not getting enough sleep. That is what causes problems.
Heck its there bodies and there perfomances. When they get to a meet and suck And look like shit during training sessions all you need to say is see, I told you so. They may have the leanr the hard way. That is what i have done with teamates and athletes of mine.