Was trying to figure out if I really needed to display both plates that the DMV sent me. I guess so.

Cal Veh Code § 5200. Placement when one or two license plates are issued

(a) When two license plates are issued by the department for use upon a vehicle, they shall be attached to the vehicle for which they were issued, one in the front and the other in the rear.

(b) When only one license plate is issued for use upon a vehicle, it shall be attached to the rear thereof, unless the license plate is issued for use upon a truck tractor, in which case the license plate shall be displayed in accordance with Section 4850.5.

I also ran across this:

§ 4461. Improper loan or display of documents, plates, or disabled person placards; Violations

(a) No person may lend any certificate of ownership, registration card, license plate, special plate, validation tab, or permit issued to him or her if the person desiring to borrow it would not be entitled to its use, nor may any person knowingly permit its use by one not entitled to it.

(b) No person to whom a disabled person placard has been issued may lend the placard to any other person, nor may any disabled person knowingly permit the use for parking purposes of the placard or identification license plate issued pursuant to Section 5007 by one not entitled to it. A person to whom a disabled person placard has been issued may permit another person to use the placard only while in the presence or reasonable proximity of the disabled person for the purpose of transporting the disabled person. A violation of this subdivision is a misdemeanor, punishable by a fine of not less than two hundred fifty dollars ($ 250) nor more than one thousand dollars ($ 1,000), or by imprisonment in the county jail for not more than six months, or by both that fine and imprisonment.

...

(d) Notwithstanding subdivisions (a), (b), and (c), no person using a vehicle displaying a special identification license plate issued to another pursuant to Section 5007 may park in those parking stalls or spaces designated for disabled persons pursuant to Section 22511.7 or 22511.8, unless transporting a disabled person. A violation of this subdivision is a misdemeanor, punishable by a fine of not less than two hundred fifty dollars ($ 250) nor more than one thousand dollars ($ 1,000), or by imprisonment in the county jail for not more than six months, or by both that fine and imprisonment.

Hmm... I always wondered when people bounded out of their cars parked in the handicapped spots...