I'm pretty sure the CA vehivle code only requrie the front plate to be "displayed" above 18" from the ground in the front area of the car. No mention of it needs to be on the bumper.
I have mine in my room too. There is no way in hell I would put holes on my car for no good reason. front plates doesn;t serve any law enforcement purpose if you think about it. It is simply a revenue generating device for local authorities.
