Ain't technology wonderful

Hidden cameras to monitor aircraft passengers
One plan Airbus is considering, says the firm's cabin security expert Rolf G�decke, involves hiding a tiny camera inside the light fittings above each passenger seat, surrounded by a ring of infrared LEDs. The cameras will normally work with ambient light, but switch to infrared when the cabin is dark.
...A less ambitious system, which Airbus is now fitting to all its new planes, will monitor the area behind the cockpit door.
..."Two cameras leave a blind spot," says Stein. "If carefully sited, three give a hijacker no hiding place."

"Hiding place." Right.

This is clever as all get-out, and given the ridiculously small expense of security cameras these days it's certainly a good idea to let the pilots monitor access to the flight deck. But remind me: How many planes have been hijacked by someone who left his seat unnoticed, hid near the flight deck door unobserved, and leapt through the door unexpectedly as a pilot opened it to get a sandwich? Were any of the planes taken that way on 9/11? Has there been any threat of such since?

Also: From a security standpoint, how would you justify not putting one in the bathroom?