Completely on-topic, Yankeeclipper is spot on: drinking should not be a part of an official visit, whatever the bonding situation, as it's illegal.
If the question is underage drinking, it is also illegal. However, I believe we're pretty much the only country with a drinking age of 21, and the rest of the planet isn't in a basket wondering where they're going with a drinking age of 18.
Our children will be exposed to pretty much everything at college....that's part of the wonderous experience that is college: choices, mistakes, questioning, and learning in a semi-protected atmosphere.
I, too, have seen friends of my children in their coffins and in comas as a result of substance abuse. I've also seen friends of my children go completely mad-dog after having been raised with an iron hand when they were finally let out on their own.
All we can do is try to instill judgement in the little darlings. As my old Dad used to say: "Toughest job in the world and there's no training".