This probably had something to do with the fact that my dad shot a burglar and it made the news . . . .
Word gets around.
That works for the folks that have heard about the shooting, but not having the car stolen by a stranger was largely a matter of luck.
Shooting an intruder is a harsh, but lasting, lesson in deterrence. It's like the APCs and artillery pieces that sit outside the front gate of an Army base. It says, "We're bad. Don't mess with us." But unless you can post an armed guard to watch your stuff 24 hours a day, leaving the keys in the car is still not a good idea.