I was about to get sent home from college today, the centre manager thought the roof was about to blow off again an it's a pretty new building.
I can't count how many times we were evacuated from my school in Florida over bomb threats and stuff like that. One time someone from a school pay phone claimed they saw someone with a gun so we were locked in our classrooms for 3 hours while the police helicopter landed in the middle of the school and a team searched the place. Didn't search people though.
They wouldn't even let us outside if it started lightning because some kid in another state got hit by it while waiting for a school bus.
I still can't see why schools think it is a good idea to congregate people in the same place when there could be a bomb/mad gunman on the loose. Surely it would be an easier target?