Get off bike on crosswalk? I go to school at Lafayette, CA. Can't find the local laws here, but people sometimes shout at me to get off my bike on the crosswalk. Even though many other students ride over the cross, I'm wondering if I should not. There seems to be no problem with it, usually there aren't many people around. 

EDIT: Usually I bike on the sidewalk, but started using the bike lane. There's traffic with little space for bicyclists a lot of the times, so I usually turn onto the sidewalk again. When there's a green light on the right-most lane, other bikers/pedestrians cross (move parallel with the traffic), so I follow since the direction is with traffic. I usually take this into account when biking on the sidewalk, so that I wouldn't have to stop to push the signal button. It looks like there's two paths for bicyclists to take: the bike lane when the light signal is green for cars, and the crosswalk, where bikers should disembark and walk with pedestrians, also when the traffic light is green? If so, can I ride on the sidewalk (allowed in Lafayette) and switch onto the road when the traffic light is go?
Here is a good reference for California's bicycle laws.   Lafayette's laws are here.

I found nothing prohibiting riding on sidewalks, and nothing specifically mentioning riding in the direction of the crosswalk.  However both the state and city codes require bicyclists to yield to pedestrians in crosswalks.