Max - armed is armed whatever way you look at it, don't forget that the hijackers were carrying box cutters, not something you would normally give a second thought to. You are advocating passengers taking on board syringes, etc!
I think flugpants sums it up, there is a time and a place for humour and in front of airport security when they have a very serious role to carry out, especially these days, is not the time to try and crack a 'weapons' related joke!
Call me grannified, humourless, whatever - but I wouldn't want to see another Sept 11th happen because someone brought a penknife, syringe, etc on board and used it on the cabin crew.
Julian.