Yeah, I remember that one of the things I'd always do when I was single and hooking up was pull out my phone and ask girls to give consent on camera. Totally normal behavior.
I'm sorry but this has nothing to do with booze. There's a gulf here between a drunken hook-up (which are hyper common) and what went down in this situation, best exemplified by the fact that the girl was okay with going to bed with only one of the guys (even with booze involved), not that he invites all his buddies to barge in like a bunch of animals.