My kids high school has armed cops in it. We're not a high crime area, but the cops are there. I have no concerns that there will be a school shooting in her school. Even her grade school, which was always locked up tighter than supermax prison, had a security guy who was armed (he was a retired cop and all parents were notified, which helps spread the word that you will be stopped FAST if you try to get famous shooting up that school. I dunno, maybe this is a better model than proundly declaring schools as "Gun Free Zone except for the guns you bring in! Have at it!".
OR .... we could cancel the constitution instead.