We already have laws that make it an offence to leave the keys in the ignition of an unattended vehicle
That's interesting, I've worked at places where the policy was NOT to remove the keys from an unattended airside vehicle, the theory being that it can be moved in an emergency by anyone without the need to locate the individual with the keys.
in my experience the airport operators we're too busy allowing security/ground ops to shaft people for things like driving without a fastened hi-viz to entertain a reasonable debate about this kind of thing!