I don't have parties at my current apartment. Too damn small.
But at my old place, we'd have people over to drink all the time. It was just understood that if they were trashed, then they weren't going home. If someone passed out, we let em sleep until they woke up. 3 or 4 beers was borderline, we'd always offer them more beer and a pillow.. some people would stay, some would go home.
If the guys wanted to stay, and were already asleep, you shoulda let em sleep. No harm in that. How would you feel if you had gotten a call saying "You have a collect call from an inmate in XXX county jail, will you accept the charges?" And someone was on the other end asking you to come bail em out. You coulda just screwed them over because you didn't want em to sleep 4 more hours. It doesn't take much these days for someone to get a DUI...