Anti theft device maybe, but the darn bikes are so light any jerk could just whip that gas bike into a pick up truck. I never leave mine unlocked ever, even at home, a guy across the street from me has 4 motorcycles, 3 ATV's, and had a brand new Yamaha ATV stolen from his garage,I never asked him if he locked his garage. I have friends that come over to my place and he thinks one of them stole it. He always giving my friends dirty looks when ever they come by. But I don't think a kill switch is much of a deterrent to a thief, especially with the lightness of these machines.