From New Scientist:

Airport security guards already use hand-held electromagnetic wands to detect metal hidden under clothing. The same wand can also sniff for traces of the gases some explosives emit into the air.

If the passenger is a suicide bomber who realises the wand has found something, the guard might not have enough time to pull out handcuffs or a gun. So the new wand will have a hidden secret – a transformer which steps the detector’s battery power up to 100 kilovolts and feeds it to disguised metal electrodes at the end of the wand.

If the wand gives a silent warning of explosives, the guard can then subtly slide the pads onto the passenger’s neck or hands and press a shock button. The patent reassures that the effect is “temporary and reversible”.

“Hidden Secret”? Guess what? They know now!

No, it sounds like a good idea. Passengers will line up to get accidentally electrocuted by some clumsy TSA employee. Soon they’ll even have their own code words for their faux pas like “fried eggs” or “Abu Ghraib”.

Since the cat’s out of the bag, why not just put sniffy bits at the end of a loaded rifle and rub that over passengers?