One more thing. California law does not prohibit merchants from asking for ID as long as they don't record the information:

Civil Code Section 1747.8 says in part:
(d) This section does not prohibit any person, firm, partnership, association, or corporation from requiring the cardholder, as a condition to accepting the credit card as payment in full or in part for goods or services, to provide reasonable forms of positive identification, which may include a driver's license or a California state identification card, or where one of these is not available, another form of photo identification, provided that none of the information contained thereon is written or recorded on the credit card transaction form or otherwise. If the cardholder pays for the transaction with a credit card number and does not make the credit card available upon request to verify the number, the cardholder's driver's license number or identification card number may be recorded on the credit card transaction form or otherwise.

Full text at
http://www.privacy.ca.gov/code/cc1747.8.htm