I took a Segway tour in Chicago this summer. Part of the tour takes you by the water. I asked out guide if a segwayer had ever fallen in - the answer was yes, sort of. They did lose a Segway in the lake, but the user jumped off before going in herself. The worse accident they had ever had was when a guy went over the front, smashing his face, after using it incorrectly and accidentally enabled an auto-stop mechanism, where the Segway basically shuts off.<p>You have to lean forward to move forward, which makes me think this guy either passed out or hit some rough terrain and the machine just slid off the cliff.