First off, look at the code here:
http://www.leginfo.ca.gov/cgi-bin/di...le=21200-21212
Basically, a rider & bike is legally just like any other vehicle operator on the road.
It won't work this time, but from here on carry a state ID card, or some other type of photo ID. When the cops stop you, present this ID, and not your driver's license. In most, states, you are required to ID yourself to an officer, but you don't need a driver's license for a bike. This befuddles cops enough to keep you from getting a ticket.
$150 seems steep, but the law reads 'vehicle code', not 'motor vehicle code'.