Reminds me of an incident that happened many years ago when an old drinking buddy of mine worked as a bouncer at a roadside tavern. His truck was constantly being burglarized while he was on the job. He tried various alarm systems but, as you noted, they were mostly ignored in the crowded tavern parking lot.
Out of frustration, he wired two oil burner transformers to the truck body so a would be thief would get a 5000 volt shock when they entered the cab. It worked very well for a few months until one night, he found a dead body lying next to his truck after he got off work. It was an older, well known thief who had several B&E convictions. He had a heart condition and the shock killed him when he tried to break into the truck.
To make a long story short, my buddy got in serious legal trouble for booby trapping his truck. What really gets me though is, the thief's family hit him with a wrongful death suit! He was in court for a couple of years and I lost touch with him so I don't know how it all ended.
I guess this is why you don't see high voltage alarm systems on the market.
