Well, I don't know if myback can make knifing a car equal to knifing a player, so I doubt that cops will ever be able to cuff people inside cars. I would assume that it's not breaking the rules since if a cop were to try to arrest people in a real life situation, some people may jump inside their car to escape. I'm sure new rules will be put into place regarding cars, but since they are so new not everything has been considered by the admin team yet, especially considering that yesterday was a tiring day for much of the admin team members.