It won't even take an actual attack to provoke an extreme response. Imagine, for example, a troublemaker group putting together a fleet of 100+ consumer-grade

It won't even take an actual attack to provoke an extreme response. Imagine, for example, a troublemaker group putting together a fleet of 100+ consumer-grade drones with empty spray cans attached and painted as to provide the illusion of a chemical or biological attack. What does security do? Ignore it all, or shut the place down? I don't see an intermediate response happening. Or, imagine the same thing being used as a diversion to a real attack elsewhere. Waiting within viewing range of the exits, for example. In situations like this, I think I'd prefer that the majority of security be covert, mixing in the crowds.