It's bad enough I have to wake up to people's cars breaking noise ordinances at 3am when a cat jumps on the hood or a heavy truck happens to drive by.

Now I have to get sprayed with fart spray when a random guy touches a random car as I'm walking by?

That only makes the security system even stronger, because now the random guy not only gets sprayed by fart spray but also gets beaten up by you, and my car is even better protected. And knowing that, the random guy will be even more afraid to mess with random cars.

What's in it for me? I intentionally don't have a car and I don't feel any obligation to protect yours for you.

All I get is the negative consequences of the decisions of strangers who do want cars.

Oh I mean, my bike can spray fart spray too. I've had 2 bikes stolen before, and wished they doused their thieves in fart spray. What's in it for you? Thieves fear fart spray and stop stealing stuff, and they'll also stop stealing whatever other assets you have or plan to have.

I'm sure fart spray wouldn't keep you from being charged under any number of booby-trap laws.