Passive Alarm System

I parked beside a car with a sticker on the window. It was one of those small stickers about a security system that comes on windows from the car factory. This one said, “Warning! Passive Security System.” I wondered what a passive security system does. Does it wait until the thief steals all your stuff before it goes off?

Does it beep or does it say, “I wish you hadn’t done that?”

I had to know, so I smashed the window.