Wow... what a waste. Now they can notify in seconds the police who will be there in minutes. Amazing.
Take that $100k per school and add those auto-closing door that they have for fire separation to every classroom.Have them be locked for outside access. And throw a layer of ballistic material down the inside. Add some ballistic material to the walls.
When someone pulls the "shooter" alarm, just like a "fire" alarm, the doors will close and the sirens will sound.
Now, this wont stop all deaths, but it will prevent the shooter from moving from room to room. And it will make the "bunker in place" method that most schools employ actually viable.
But no, instead some podunk school district gets suckered in by a scam of a system in SDS/ShotSpotter.