At work, if I have to warn kids about something, the second time I tell them they will have to leave if I tell them again, the third offense I kick them out. No exceptions. I've been yelled at my irate parents, but you know what? If you want to bring your noise machine into a pet store, don't let them bang on the cages/run around/scream/etc.

Ilovereptiles, thanks for the url! I may become a regular there!