OT but it reminds me of an interesting experience going through security about 6 months after 9-11 when I was still in the aviation business. I was in the flight control (FBW) sector and I had an avionic unit used on the 777 with me as hand luggage. These are generally about the size of a paperback book but a bit thicker - about 50mm, black and on one edge is a row of connectors. This unit however was non-operational and had been previously used in high temperature testing in an environmental chamber. Given what it had been subjected to it could never be used on an operational aircraft.

Now as anyone in the aviation business knows, to avoid any possible confusion with real units destined for operational aircraft, spares etc, it is customary (maybe mandatory - can't 100% remember) to have the wording "NOT FOR FLIGHT" stencilled on test / life expired items that should never be used operationally on a real aircraft.

So there I was going through security and they pounced on this item and this wording caused much discussion and debate among security staff and about three levels of the BAA security supervision / management were called down as no one would make a decision! Their stance was "you cannot take this in board as it specifically says it is NOT FOR FLIGHT". No amount of discussion, explanation as to the proper purpose of the words would budge them, as far as they were concerned it could not possibly be taken on-board an aircraft.

I had to leave it behind and not take it - fortunately I was parked in the short-term car park so was able to pop back.

Bl**dy annoying at the time - but I guess I can't blame them really