1. Find any vehicle.
2. Put on all the parts needed.
3. Drive away
4. Leave the car anywhere and log out.
5. Wait for a couple of hours.
6. Log back in.
7. See that vehicle is not where you left it.
8. Run back to the spot where you first found the vehicle.
9. See that the vehicle is there again but without any parts you put on or gear you left inside (as if you never drove it away, which proves that it was not taken by any other player).