I've got friends who work for NASA who tell me that the latest they've heard about are people leaving thumb drives in parking lots of top secret installations. The idea being if you find a thumb drive in a parking lot, you'll pick it up, and then plug it into your computer, in hopes of finding the owner. Once plugged in, the Trojan goes to work and starts sending files to other countries. They suspect China, of course. As a result, NASA has said that external drives and thumb drives are no longer allowed.