[GregoryFul]

Consider the following: you are sitting by a nut job in a crowded theater. He starts yelling fire, you look around and see no fire. Do you muzzle him, or let a stampede happen?

[Cicero]

On the other hand, if someone shouts "Fire" in a crowded theater, you should look around, and if you see some smoke, the proper thing to do would be to calm the shouting fellow down to prevent a panic, while you organize an orderly evacuation of the theater.

There is smoke in most of the cases we're talking about here. So somebody ought to at least take the trouble of investigating. And if there is a fire, they should tell people about it in an orderly fashion.