IMO open carry makes people an easy target for predators. Predators size up people as part of their profession. Showing them that you have a weapon gives them the advantage IMO. Just my to cents from the peanut gallery.
To me, open carry means you are the first to be dead.
Public schools are a nightmare of crime and abuse to the teachers and staff. Teachers send students to the office for discipline, the office sends them back to the teacher. Fights break out and the teacher is best not to get involved, just call LEO.
The retired teachers I know say that a teacher carrying a gun is a no no. The reason is that children should not be in an environment where they do not feel safe. Many children do not get fed at home and there are no parents, just adult children. Also, the teachers union is made up of extreme liberals, they put on the blinders that there is no evil in the world and you should not remind them or the kids that Evil exists. Liberal teachers are NOT going to arm themselves. The Evil to the Liberals is that guns exist.
I don't know if taxpayers are willing to foot the bill for school safety with inflation and rising taxes killing family budgets.
A secure building with steel doors(inside and outside) is a good start, and it is going to cost two fortunes.
As xsn10s mentioned, the parents are going to have to get involved with the schools boards and actually learn what is going on in class. Parents should have the ability to "audit" or attend school with their child in the class rooms, wouldn't that be revolutionary!