I've never seen anyone drunk at Disney, but I'm definitely not disputing anyone's observations.
However, Disney does just slightly more than zero to control other, sober bad guest behavior, so I'm not sure why anyone expects this to be any different. Line-cutting, scream-chanting, loudly narrating over the attraction soundtracks, parade spot crashing (and I don't mean "saved" spots, I mean pushing folks out of the way who've been waiting), repeated flash photography after warnings--these go on and on with zero CM response. I just don't see them jumping in here to decide who's had too many.