The ability to rent vehicles needs to be restricted from all jobs, except for citizen and possibly mayor. A couple of times now have I seen player with the tow truck driver job attempt to rent a vehicle, pay for the vehicle, and no be allowed to drive it because of their job. Once they quit their job the car disappears and the player loses the money spent renting the vehicle they could not even drive.
I've only seen this happen to tow truck drivers so far, so i'm not actually sure if a police officer or medic can rent vehicles in the first place and tow truck driver was just missed and has to be added to the restriction.