When congress asked Mrs. Devoe (our new prospective Secretary of Education) about whether guns had a place in the public schools, I think she could have pointed to this and said, " If rioters are approaching your child's School, what would you want the people protecting them to be armed with?"
If I was a principal of a public school nowadays, believe me I would keep a shotgun.
But what if it's a riot like the one in Berkeley? How are you going to stop that danger?