The weak point in the system is the notification alerts.
Just today there is a news story about a failure of a similar notification system.
http://wncn.com/2015/07/23/unc-emergency-notification-system-failed/
Actually, it’s a great idea.
Could be worked out by a simple text message to the CCW’ers cellphones. Simple three letter code sent, a pre-determined muster point, with instructions have already given, and you have instant security in place.
Hell, flash mobs use it. We should too.