Have any of these "code red" security upgrades prevented a school shooting event? How would we be able to know? They don't expect to arrest people on their way

Have any of these "code red" security upgrades prevented a school shooting event? How would we be able to know? They don't expect to arrest people on their way to a shooting. They expect that potential shooters will be scared off from even trying. We do know that the number of shootings keeps going up. The culture of fear is caused by the fact that there's something to be afraid of. The odds are low but the consequences are horrific.