"If they do opt out, we just want to make sure, for example, on Christmas Day," Mr. Pistole said, in a clear reference to the underwear bomber, that "they receive a thorough pat-down so they don't pose a risk to that plane."

Umar Farouk Abdulmutallab, the so-called "underwear bomber", is sentenced to life imprisonment for attempting to detonate a bomb on Northwest Airlines Flight 253 in Detroit, Michigan.

Civil liberties groups say the FBI and federal courts have dealt with more than 400 alleged terrorism cases, including the successful prosecutions of Richard Reid, the "shoe bomber", Umar Farouk, the "underwear bomber", and Faisal Shahzad, the "Times Square bomber".

Jokes are easy, like Mr. Schneier's crack on having to remove shoes: "It's a good thing the shoe bomber wasn't an underwear bomber."

If someone is arrested one of these days and is immediately, because of his M.O., referred to in the press as the underwear bomber, you'll know I was onto something.

An underwear bomber who attempts mass murder on Christmas Day is bound to leave many people upset and a few unhinged.

Lawyer discusses 'underwear bomber' plea - video (1min 23sec)

Umar Farouk Abdulmutallab (born 1986), the "underwear bomber"

STEVE: And the shoe bomber, the underwear bomber, all these variations of bombers, they were not when people were flying from Orange County, California, 500 miles north to Northern California.

And another note: This incident has been linked to last Christmas's would-be underwear bomber, Umar Farouk Abdulmutallab, who also used PETN and spent time in Yemen.