Motion Sensative car alarms suck! They are just noise pollution. If you hear a car alarm go off, you don't think, oh I better call the police cuz a car is being stolen, you think, "oh a cat just walked by an oversensative car alarm. I wish the owner of the car didn't have that damn alarm going off at all hours." No one ever thinks the car might be broken into. That's what car alarms are supposed to prevent, but 99.9% of the time they go off for no good reason.