That key sensor may only be on the key slot, but that sensor must be activated in order for the ECU to work. I was reading all about the imobilizer system in our cars, and without a key or an electronic bypass, there is no way to make the ECU work, other than actually replacing the ECU with an ECU with the immobilizer bisabled. So, unless they have an extra ecu handy, or have something that can dupliucate the particular signal from the chip in your key, they'll have to think of something else. At any rate, if someone really really wants your car, they'll just put it on a flatbed truck and tow the bitch away, simple as that. Nothing is going to keep someone from getting your car, not matter what you do, you can just hope what ever you do makes it enough of a pain in the ass in order to disuade them from steeling yours.