I meant immobilisers,the ones that cut fuel lines/enables ignition system with the immobiliser key (ussually attached to car keys).
Unless the thiefs are so high tech,it is not posible to break this code (usually transmitted by radio waves when you press the immobiliser key) to identify as the owner. Without this key it is not posible to start the car.
I know stuffs like alarms,tracking devices don't guarantee total security. But it is good they be there to improve security.
i too