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.
This whole thread has degenerated into a urinary dispersal match and that's a shame. The fact is, there is a real discussion to be had about the real possibility of a terrorist missile attack on commercial airliners. It may or may not be the case here but let's at least keep an open mind on BOTH sides of the debate.
And if on inspection it is a smoldering cigar butt, you put it out and let the show go on.