The underwear bomber's Christmas Day attack has prompted calls for the increased use of full-body scanners at airports that would strip-search passengers down to their naked bodies.

So to protest the use of the so-called Nacktscanner (naked scanner), members of the Pirate Party in Germany organized a "fleshmob" of people who stripped down to their skivvies last Sunday and converged on the Berlin-Tegel airport. They posted a video of their protest to YouTube, with soundtrack provided by Muse's song "Uprising." The lyrics articulated their protest: "They will not force us. They will stop degrading us. They will not control us. We will be victorious!"

Warning: The video above has mild nudity so may not be safe for work.

The protesters marked their bodies with a number of messages such as, "Something to hide?" and "Be a good citizen – drop your pants."

One woman has the word "diaper" scrawled on her lower back with an arrow pointing to her underwear and the word "prosthetic" printed on her leg. The word "piercing" and an arrow point to one of her breasts. Another woman dressed in a beige sweater and flesh-colored tights wears a sign reading "pixelated." (To address privacy concerns, security officials say the scanners can be programed to produce a blurred, pixelated image of passengers to protect their modesty.)

The full-body scanners use high-frequency radio waves to produce an image of a passenger's naked body beneath clothes. Anything a passenger is carrying against the body – weapons, drugs or explosives – would be exposed. The scanners would also reveal the presence of prosthetic devices and breast implants.

As such, there have been privacy and legal concerns raised about the invasive equipment, particularly because it's unclear if the scanners would be able to detect explosives hidden in body cavities and would therefore likely provide only minimal security.

German and Dutch authorities announced this week that they would be working together to test and possibly deploy full-body scanners in the two countries over the next year. The move comes in the wake of concerns that a would-be bomber was able to board a flight from Amsterdam's Schiphol airport on Dec. 25 wearing packs of chemical explosives concealed in his underwear.

Although Amsterdam has been conducting a test pilot of full-body scanners since 2006, the armed passenger was not scanned by one of the devices before boarding his flight to Detroit. European Union regulations do not currently allow mandatory use of the equipment.

The scanners are currently being used in about 19 U.S. airports, though the Transportation Security Administration has plans to deploy about 300 more. The machines are used on a voluntary basis only; passengers can opt to have a full-body pat down instead of being scanned.

Hat tip to Wired's Stephanie Degen for translation assistance from German to English.