its abit of a legalaity thing this, you cant leave your keys in the car whilst its running, cars not secure so anyone could just jump in . however as you can take your keys out and lock your car then the car is secure and even if someone broke in the steering lock would be on and also once its timed out the car is dead. its the same as the point of starting your car and leaving it running during the winter to de ice before you drive it. , police turn a blind eye to that one. and one last thing , what about these keyless remote starters. that can start the car by a button remotely whilst the car is still locked, there not illegal.. i think you could get off with the timer thing for the safty aspect of the car is secure and the keys are in your pocket. totally different when you leave the keys in whilst its running