Agree with you 100%.
The lowest cost option where school administrators would NOT have to hire a single additional employee, or so much as put 1 foot of razor wire around any school perimeter, would be to simply change a few laws in all 50 states where responsible, adult teachers have the option to carry a concealed weapon on their person all day, every day on school grounds.
Decades ago when hijacked jets were the worst we could expect, Archie Bunker offered to solve the problem by having every jet passenger bring a gun aboard a jet. Problem solved.
Sound too extreme?
Then get prepared for the inevitable future school/workplace/"GUN FREE" zone massacres that statistics imply will happen again in the not to distant future if you limit yourself exclusively to the use of non violent measures to deter real violence
