I reckon even when they're working perfectly they are still a pain in the arse.
I've had the stupid thing cut the engine on Albany Highway because I got out of the car to check the letterbox and it thought I'd been jacked.

I've lost count of how many times people say to me "you won't need the code, I've disabled it" only to find that the moment you disconnect the battery all bets are off and the siren starts wailing.