Famous hacker Kevin Mitnick was detained U.S. customs agent when his plane from Colombia landed in Atlanta on September 16. He was questioned for four hours and released. CNet has a pretty detailed account of what happened, but the most interesting part of the story, to me, was the list of stuff the authorities found in his luggage.
In his luggage, they found a MacBook Pro, a Dell XPS M1210 laptop, an Asus 900 mini-laptop, three or four hard drives, numerous USB storage devices, some Bluetooth dongles, three iPhones, and four Nokia cell phones (with different SIM cards for different countries).
They also found a lock-picking kit and an HID proximity card spoofer that can be used to snag data stored on physical access cards by swiping it in front of them. The data can then be used to enter locked doors without having to make a forged access card. Mitnick says he used the device in a demonstration about security in his speech in Bogota, but that the customs agents' eyes lit up when they saw it, thinking it was a credit card reader.