There are a lot of areas of confusion about some California driving laws. This was discussed in article that is part of an on-going series in the San Jose Mercury News that covers readers' questions about driving. The article supposedly provides some final answers about some very common driving questions. Since the article doesn't site many of its sources, it's tough to trust it 100%. The article does make some interesting statements.
One of the biggest questions in California is about something called free right turn. Many larger intersections have right turn lanes that are separated (channelized) from the intersection by a traffic island. These lanes rarely have signals or signs directly associated with cars in the lane. The confusion comes from how to use the lane when there is a red light in that direction. In most cases, a right turn is allowed on a red light only after a full and complete stop. However, when there is a separated lane, the car may treat it as a yield. In other words, it's OK to precede on a right turn as a yield on a red light (if safe) for separated right turn lanes.
Here's the funny part. There is no law on the books in California that actually make this declaration, as far as I know. The free right turn rules seems to come out of the same absence of law regarding the requirement for a stop on red for those lanes. It's important to note that this rule only applies if the traffic signal is after the segregation of the right turn lane (which does make sense).