I have attached a transcript of how nasty things get with the police officer in Court.  The police always botch the procedures, so they are very careful with folks who know what they are doing or they will get embarrassed.

Too many people plead guilty to DUIs for no reason.  Never hire a lawyer to plead you guilty.  It is like hiring Jack Kevorkian, M.D. to kill you, just do it yourself and save your family some money. A lot of DUI lawyer are thieves, at least 90%

Here are the facts I gathered regarding our earlier discussion.

I have heard that they cannot detain you for purposes of ascertaining your ID, but I have no idea of the source.

Keep in mind, that I do not know if it is a crime, but I did check after my encounter and the DMV DOES SAY YOU MUST HAVE IT:

License in Your Possession

You must always have your driver license with you when you drive. Show it to any police officer who asks to see it. If you are in an accident, you must show it to the other driver(s) involved. (More information about accident involvement).

http://www.dmv.ca.gov/pubs/hdbk/misc_lic_info.htm#carrylicense

The police officer told me this as well.

My partner who is an expert at this stuff told me the exact same thing and said it was a $300 fine. I have no personal knowledge.