Used to do this with the school economic system but they gave out detentions for selling shit for school economy (There was once this kid in chorus who was a smarties dealer, literally made stacks off smarties)
One of my teachers from 7th grade got arrested for always being high during class (discreetly), and apparently died of overdose in jail lmao
Gum is allowed in our school as long as your not being annoying with it (opening your mouth wide every chew)
Actually gum is a must while exams at my previous school The chewing is good for your brain or something (i know it sounds weird but its true)
They told us we could do it because it stimulates memory or focus or some shit. Not really good for your brain but helps with those activities.