Yeah that is what I want to see, a bunch of drunk adults ridding bicycles down the street,
You should add to your negative list:
#7 Possibility that one friend will hit a pedestrian.
#8 Possibility that one friend will hit someone's parked car.
#9 Possibility that one friend will ride out in front of a truck and become ground meat.
Negative item #9 alone is enough to forget about the whole deal.
Driving (or riding a bicycle) while intoxicated is stupid. There is nothing cool or positive about it.
What is wrong with going out for a ride to drink coffee or soft drinks? Or go for a ride, everyone has a sleeping bag on their bike, meet at your place, have a party then sack out in the living room?