You may pour as much scorn as you like, but this is the reason given to security personnel, during their training, to be particularly vigilant over these tiny items.
We know for a fact, because this is well documented, that flight attendants were killed before the hijackers gained control.
If you really want:-
http://www.airdisaster.com/special/special-0911.shtm
.......and, before you say another word, we're on the same side!!