We had a ton when I was in high school. I think we even had them 3 days in a row at one point. This was before 9/11, so no one got in huge trouble over it.
When I was in school there was only one. When Dwyer was in school they only had stone tableted in stoning threats. Good times. This one time this one dude in his independent study shop class came in with these 2 stone tablets. I think he got them near a burning bush.