Stephen D. Levitt, co-author of the excellent book Freakanomics says he was on a flight a few days ago, and before the plane was about to take off, the flight attendant announced:
"According to the reading on my equipment up front, there is still one cell phone turned on, so please check that you have turned yours off."
Obviously, she has no equipment for detecting this, but you should have seen the passengers scramble to check their bags. Except for me, of course. My laptop hummed happily along under the seat in front of me. Still, brilliant on the part of the flight attendant, although I think it would have been more convincing coming from the pilot.
He also adds this tidbit:
… TSA just confiscated my deodorant and my toothpaste. Of course they let me keep my contact lens solution. Hmmm…if I were a terrorist, don't you think that I could figure out how to take the top off a bottle of contact lens solution and put my explosive liquids in there? It is totally pointless to enforce rules which impose costs on innocent people, but are easily circumvented by terrorists. Can anyone think this is accomplishing anything productive?
