Selling a car at the market magically makes a vehicle scam proof. But you can't sell a vehicle to a person without there being a huge risk of being scammed, which technically is not against the rules. On top of which, you can use /showvehicles when someone steals your car to show the location as soon as they step outside of it. None of this makes any sense in the world of RP, so a command to sell a vehicle should be implemented.
/sellvehicle [license] [player_ID] 50000
and
/tradevehicle [license] [target_license]
Otherwise, there should be an official way like an escrow at a bank to pay taxes on such transactions and lock both assets or also insure scamming is impossible.
Additional info:
Once a transaction is completed, a scammed vehicle that was suppose to be traded should be treated the same as a stolen vehicle. However, it is not placed as one of your owned vehicles, which is why this command is needed.
