Only problem is that if someone is killed by a Booby Trap, the person creating and setting the trap are liable for up to murder.
I was so pissed when I had an expensive radar detector stolen, I thought about putting black powder in the case and wiring a model rocket engine to the power connector of an old unit. And then placing it on the dashboard for a thief to see.
My dad had one of the Judges he knew at the criminal Court call me to discuss my idea. Needless to say I came to the conclusion it was not a good idea.