I've certainly gone wine tasting on my bike. We used to take our mtbs over to the Napa Valley during crush (way before the commercial tours). Only way to do it when everyone else is in bumper to bumper traffic. However, we truly taste, we do not drink.

I just let people be. If they are drinking no more than they can metabolize, it's up to them. RUI or DUI, it's all the same.