In the red dot, george "throws up from the hennigans" and jerry says "but you don't drink"... there's an episode (can't remember which one) where both jerry and george are drinking a beer. and I'm sure there are at least 2 other ep's where george is drinking wine.
it's maybe different in the US but does it not count as drinking if it's beer or wine??
on the same line, we only really see elaine drinking in the betrayl when the key to her vault (peach schnapps?) is widley known.
are there any other eps when people are "comedy" drunk?