so my mate has one of those breathalyser things in his car, if he's had a drink he cant start the car and even when he's driving it periodically requires him to blow into it and if he fails it shuts the car off

...so is it possible to set up a system where u have some kind of transponder or something in ur pocket and the alarm/immobilisor sends out a signal looking for that transponder every minute or so and if its not present it shuts the car off? ..say for instance if uve been carjacked, u cant just take out the keys and say sorry id rather not ..if u hand over the car and down the road ur car doesnt get a return signal from the transponder in ur pocket it shuts down the car.

..or better yet, something like a remote activated turbo timer so u can wave good bye to ur car knowing itll turn off in a minute ..or something like that.