i remember reading on some website many years back where a guy rigged up a washer squirter nozzle in the side mirror that was aimed about where you'ld be standing if you were trying to gain access to car, He then made the lock pull look like car was unlocked and if you pulled on handle to open door without disarming it , it would squirt some kind of nasty mix of pepper spray, he had formula posted and how to set it up, some switch inside door, when door handle is pulled it completes circuit.
just enough to blind him anyway, hard to steel what you cant see