What would happen in a NY party with underage drinking?

I'm going to a party my friend is hosting later this month. The thing is, this is a frat party so there's gonna be college minors or whatever getting drunk and all. I've never been to a party in NY before, much less a frat party, as I don't live there and I'm kind of just hoping that the real thing doesn't live up to the legend as far as like, cops busting in with riot shields and such arresting everyone there lol. So my question is basically, if cops come, how much trouble would the minors be in? And how much trouble would someone like me, who is of age, be in for not 'stopping' them? Or are partys in NY just like, not the cops thing because they have other stuff to deal with, because that's pretty much how it is here lol unless they drinking/drugging in public