Are you saying the ETD swab was a false positive? This happened to my husband once. His C-PAP alarmed the swab (glycerin from the soap used to clean it, duh) and they did a quick frisk down his sides and legs. It was a few years ago, but I agree, I couldn't see any rational reason for it. If he had some kind of glycerin bomb (?), he could have had it stashed in a number of places the clerk didn't touch.