Been searching in vain but there was a show a couple of years ago and they would set things up to see how honest people were. In one part they'd doctored a bike to make it nearly unrideable but people would still try to ride off with it. I want to say they locked the pedals so they'd roll under your feet and the seatpost was a piece of irrigation tubing. It was hilarious to watch.
The real kicker was when a guy actually DID get away from the production crew and the police on it!