Since 2001, when an Englishman named Richard Reid tried to sabotage a flight from Paris to Miami by detonating explosives hidden in his shoes, American travelers have become accustomed to removing their shoes and sending them through scanners at airport checkpoints. Last week, a Nigerian named Umar Farouk Abdulmutallab tried to sabotage a flight from Amsterdam to Detroit by detonating explosives hidden in his underwear.