I worked for an operation in which private aircraft were contracted through a government agency. One of the requirements was that a switch be installed to disable the aircraft to prevent it's unauthorized use. Most of us considered this an unsafe requirement. Where such installations were made, the switch itself was bypassed or disabled, and in most cases, the switches were simply dummy switches to satisfy the requirement of the contract.
The only ones who should ever have any such control are those actually operating the aircraft, and that would be only the crew.