Terrorists who don't wash their hands

A couple weeks ago, I took my first plane trip in a while. It was just a short jaunt over to Fresno, but I've been away from the TSA Security insanity for far too long. . As I entered the security check-in area at Sky Harbor, I was pulled aside by a lady in uniform and ordered to extend my hand. She proceeded to swathe it three times with some sort of liquid, and I then had to put my hand over some sort of scanner. . It of course turned out negative, and I later found out from a frequent-flying colleague that it was looking for traces of bomb-making material on my hands. Lucky for me as a chemist that none of my company's chemicals are apparently on the no-no list. . Curiously, there was a guy entering the Security Zone right behind me. The uniform asked him if he was with me. "No," he answered (truthfully). "Okay, you can go," she said, and he moved along without incident. So... . Did I really look like a terrorist, or was a TSA lady just trying to justify her existence and randomly check anyone she didn't like? And what difference did it make whether the next guy was with me or not. Do terrorists only work alone? . In any event, I feel so much safer knowing that TSA is watching out for bomb-makers who don't wash their hands.