So, by that logic, any employee who just wants a few extra hours of pay can accidentally on purpose lock their keys in the car and the employer will have to pay them for it?
I don't think so.
"accidentally on purpose" god, I love that phrase.
The reality the employer could do several things to make sure such 'involuntary pay / waste work' situations never play out, here are some top few ideas:
1) The employer could fire the employee on the spot and retrieve the vehicle by whatever method they choose without the employee having any custodial responsibility for the vehicle.
2) The employee could have a CONTRACT that specifically addresses issues of potential deliberate negligence, such as locked in keys.
3 and perhaps ideally done in conconcert with 1&2)
The employer could maintain proper morale and an effective disciplinary environment where such shenanigans would be never even be considered.