Lots of restrictions on CA dealerplates.
1) Only the dealer/owner can have unrestricted use of a dealerplate. We used to put our spouses on dealerplates, but that's been a crime since 1972! (And it's being enforced). So... we plate my wife's and mom's car.
2) Dealer managers can use a dealerplate if only in conjunction with their work. There are sales-tax and income-tax ramifications concerning their use, i.e. if the manager drives the vehicle 50% personal time, there is a formula that tells you how much tax the manager (or dealership) owes. There are DMV investigators looking for dealer-plated cars that appear to be for personal use (personal items in vehicle). This prompts DMV action as well as a state tax audit. A general state tax audit (which occurs every couple years) will also look into dealer plate usage so if you have a bunch of plates, be very, very organized. Have your managers sign a dealer-plate use statement and keep in your employee records.
3) Dealerplates are to be used for demonstration purposes, not for service loaners. Again, tax issues as well.
What happens is that CA charges a cheap fee for the plates and wants to collect a "use fee" (basically sales-tax) for the use of the vehicle. Therefore, you are responsible to calculate and remit the fee. The easiest way to comply is to register the vehicle and pay the licence fee. You'd have to sell that car on a used RS but you should be disclosing demo/used cars anyway.
I only know this since my GM's wife pulled an illegal U-turn on a dealer-plated car and got an extra violation. A couple of violations can cause DMV disciplinary action (suspension of licence, for example!)
You could probably go to the CA DMV website for more info as well.
[This message has been edited by sallen1 (edited 09-15-2003).]