Will do nothing to stop the next killer, the NRA plan would.
The best thing would be to take down the "No Gun" signs, and allow anyone who is legally allowed to carry to do so.
If you disagree ask yourself: Why did the Sandy Hook killer pick that school?
Answer he wanted the highest "score" possible, and expected no resistance from first graders. These loser punks, don't want a fight, just a high score.