There's an effect, I forget what it's called, where a deterrent is effective enough that the only time you see it activate is accidentally. I believe this may be the case for car alarms. It has a side effect of desensitization, but it is still effective. I doubt most thieves smash and grab without consideration of alarms on the grounds that probably nobody will care about the alarm. Thieves want to steal without bein…
Speaking of, I'm surprised that there aren't more prank automotive devices. What if your car's horn went off semi-randomly twice a month, with a different horn sound each time? Or your turn signals made loud clicking noises that everyone could hear? Or your Bluetooth calls also broadcasted through the car alarm speaker on Wednesdays? There's plenty of room for innovation in the car alarm space.