Is the prohibition of Alcohol in the United States during the 1920s common knowledge around the world? I don't know, but just in case, I assure you that it was a thing!
A handy guide to determining whether or not your buddies have been subjected to some manner of mind control that makes them obey any order:
Step 1 - Tell them to cluck like chickens.
Step 2a - If they do, freak out.
Step 2b - If they don't, dance the victory chicken dance.
These are the sort of important life lessons one learns from reading this comic.
Diane's posing in panels three and four of this comic are a direct result of the decision to use "thump" as the sound for Diane quickly making her way up the stairs. It was so close to "thwump" that her falling over was pretty much mandatory.