They would be able to track it from the fact that the driver opened the car and then the car disappeared.
Very unlikely that the crims would be that obvious - and because unlocking the car doesn't necessarily disable the immobiliser. A more probable scenario is that car thieves use permitted access to the car to add some form of "theft enabler" to be used at a later date. Sooner or later the pattern emerges, but with a little bit of care it could take some weeks.
Biting the hand that feeds IT
