Another problem with our anti-teen drinking hysteria and associated laws&enforcement is that in plenty of places it's very difficult for kids to go to a club and see a band. Locally in Philly we a have a promoter who is dedicated to sponsoring, as often as possible, all ages shows, and this often mandates finding performance spaces where no alcohol is served, which messes up the economics of small touring a bit. Bigger performance spaces can get away with physically separating the drinkers from the under 21s, but smaller performance spaces can't and especially for smaller venues alcohol sales really pay for the band... Enforcement of this stuff varies across cities and states of course.