bcsajdak

§ 5201 Veh.

License plates shall at all times be securely fastened to the vehicle for which they are issued so as to prevent the plates from swinging and shall be mounted in a position to be clearly visible, and shall be maintained in a condition so as to be clearly legible. The rear license plate shall be mounted not less than 12 inches nor more than 60 inches from the ground, and the front license plate shall be mounted not more than 60 inches from the ground, except as follows:

[(a) to (d) omitted]

(e) No covering shall be used on license plates except as follows:

(1) The installation of a cover over a lawfully parked vehicle to
protect it from the weather and the elements does not constitute a
violation of this subdivision. Any peace officer or other regularly
salaried employee of a public agency designated to enforce laws,
including local ordinances, relating to the parking of vehicles may
temporarily remove so much of the cover as is necessary to inspect
any license plate, tab, or indicia of registration on a vehicle.

(2) The installation of a license plate security cover is not a
violation of this subdivision if the device does not obstruct or impair
the recognition of the license plate information, including, but not
limited to, the issuing state, license plate number, and registration
tabs, and the cover is limited to the area directly over the top of the
registration tabs. No portion of a license plate security cover shall
rest over the license plate number.

VicG

Yep, that means trim rings are OK, but anything over the plate itself is illegal. Same thing in NY..