Here's what you guys need to remember:

The point of official policy is not to save lives, it is to minimize legal liability exposure after the crisis. They would rather have some people die and then have an airtight-as-possible legal position when its over and the lawsuits roll in.

It's the same thing with the "no firearms in your car" policy at most workplaces. Reality shows that those intent on going postal will do so regardless of company policy. But when the lawsuits come, the company needs their lawyers to be able to point to official policy that says "we are a weapon-free zone, we did everything we could", even though that stance does nothing to protect employees.

This is fact. Plan accordingly.