We had our high school evacuated when I was a freshman, I think. Someone had spread some strange smelling substance somewhere in the school. The staff evacuated us kids while they tried to figure out what it was.
I think we had some kid sabotage the school buses once. Where I lived, school was on every day unless the buses didn't run.
And once we had a problem with a transformer that went out. I can't remember whether that was sabotage or just an accident.
But never a bomb threat or a shooter threat. (Back in those days we didn't have the term code red used at school.)