Sure, let the teachers and the custodians and the guidance counselors and the lunch ladies all carry their weapons. Heck, let the 18 year old seniors bring their guns too. Especially if they were in the Junior ROTC program. /s
But also, make them responsible for any outcome. You take down a bad guy in an active shooter situation, big bonus for you, in the millions. But if your gun harms an innocent person, or is "lost" and used in a crime, or goes off accidentally you are personally liable, not indemnified by the school system, but you the gun owner are responsible and you cannot bankrupt yourself out of that financial risk. You may get insurance if any company would insure you, at your own cost. The idea that 150 hours of training makes a person qualified to competently handle a school shooting is foolish.
And the "Old West".. read about the
vigorous gun control in the "Old West" where you had to leave your weapon with the town sheriff if you were within the city limits.