I like the one of the Prune FO who was not permitted to take her own sandwiches through security when she was about to go flying from LHR. Clearly there could have been explosive mustard or mayonaise or maybe a deadly poison in the sandwich. Reluctantly she gave up her sandwich and sped off in a hurry. After a couple of minutes she realised she had left something at security. She walked back to the area of the scanner, to find the security guard who had confiscated her sandwich as a lethal weapon, stood to one side eating her deadly sandwiches!!!