I had a funny experience today. My insurance company offered a sizeable discount if I had a passive ignition immobiliser fitted to my car. I booked the car in to one of our better "Competition Stereo" installers to do the job.
When I drove the Cobra into their installation bay, every single car parked within the premises first let out a quick chirp (as the motion sensing car alarms always do), and then all hell broke loose. There must have been 10 car alarms going off, with the shop staff scrambling around pressing remote controls left, right and centre!!!!
Life is good!