False positive

An apparently random swab test of Contrarian's new MacBook Pro at the Stanfield International Airport screening area this morning detected traces of nitroglycerin. The CATSA agent who conducted the test summoned a supervisor who explained, pleasantly, that the machine had triggered an alarm. She proceeded to check my identification and ask a series of questions about medication, chemicals, and hand creams. My negative answers turned up no obvious source of nitro, resulting in a further swab test of my iPhone, a complete physical check of every item in my carry-on bag, and a rigorous, 90% pat-down.* In all, my case drew upon...