In South Africa (where kidnapping and car jacking and murder all go hand in hand...and are very common), it's legal to have active defenses on your car. Flame throwers, electrified panels, pepper spray ejectors, etc. are all OK. From what I've been told if your car kills somebody who's trying to carjack/kidnap you, it's less than a slap on the wrist if it goes to court.

Armored car sales are also one of the highest anywhere in South Africa.