Ignition Key Cloning Security Issues

[bowler_1]

Here in the UK there are serious issues of keys being cloned after breaking into cars and cloning your key code from the OBD socket, then returning after the damage to the vehicle, i.e. broken door window, has been repaired, sometimes several days or weeks later, and just driving off in your precious BMW.
While I am now retired I was a fully trained auto electrician many moons ago and the following thought has occurred to me.
To prevent vehicle thefts of vehicles with electric fuel pumps we used to fit a switch (either a simple flick one or a key operated one) in the power supply cable, after the fuse, to the pump. This switch would be placed in a discreet position in the front of the car but somewhere where it could be reached by the driver. Normally it would be always left switched on, but if the car was left somewhere suspect or long term in a car park then you would switch it off, obviously meaning that the vehicle could not be driven off.
With modern CANBUS systems is there any reason why this same method would not work? Would it throw up an error that could only be cancelled by a visit to a stealership?
If anyone with the knowledge of modern BMW vehicle electrical systems has any comments on this it would be appreciated .
Apologies for the long winded post .