But wasn’t the legal age for beer 18 back then? And I bet especially in Milwaukee!
Sometimes Hollywood writers just don’t use facts.
Not during the 50's, the period that Happy Days was set in.
The drinking age briefly lowered to 18 in most states in the 70's, after the Constitution was amended to make that the voting age. I don't remember exactly when, but the federal government made highway funds contingent on raising the drinking age back to 21.