One of my favourite security devices is a smoke bomb in the car.
Would be thief gets in, shuts door, car locks, sets off smoke bomb and car alarm.
The idea is attract as much attention as possible, which if somebody thinks the car is on fire: will!

Smoke bombs - think about that one !!!

I used smoke canisters in the army, not only to they burn pretty hot but the smoke stuff (be it green, red, yellow, orange or blue) is a dye substance that settles on and into everything.

Would certainly attract attention but......

Mike