I'm very much an advocate of bicycling belongs on the street, that sidewalk riding often results in more collisions, and streets should be made to feel safe to ride. However the reality is some people are sidewalk riding, and this is especially common where streets feel hostile to cyclists, either because of the infrastructure and or the speed and attitude of the drivers on the street. So we should pay attention to how the law applies to sidewalk riding. Where sidewalk riding is illegal but little effort is made to make the streets feel safe for bicycling, it becomes clear that a municipality is trying to squeeze bicycling out of the picture all together by forcing cyclists into a position of feeling in danger or breaking the law.
For anyone who has every been confused by where it is and isn't legal to ride a bicycle on a sidewalk, the LADOT bike blog has started an informative series on just that question, aiming to sort out the sidewalk riding laws across all the various jurisdictions and cities of Los Angeles County. In the City of Los Angeles it is legal to ride on the sidewalk so long as without a "wanton disregard for the safety of persons or property." In some cases such as Beverly Hills, the ordinances are quite complex. Sidewalk riding is illegal there in any business district, which is defined as streets with 50% or more of buildings being commercial, but what is and isn't considered commercial business for the purposes of this law is a list that includes some things less obviously thought of as a business, like churches.
(While this can create serious conflict with pedestrians, notice no one is walking here)
For those not already aware, it is explicitly clear in the Santa Monica municipal code that sidewalk riding is illegal. In practice it is still fairly common, especially on streets like Lincoln Blvd. However from my observations reading the SM Daily Press Crime Watch column, and letters written into me, the sidewalk riding ordinance, and cycling violations in general, are often just a pretext for conducting drug searches. It seems like every other story that turns up in a keyword search for bicycle in Crime Watch, is either a stolen bike, or a bicyclist busted for drug possession after a minor traffic violation like sidewalk riding or absence of a front light. I don't know what the standard policy is of the SMPD, but I'm guessing they probably don't go sniffing for drugs in the trunk of every motorist they pull over for a minor traffic stop, especially one that is a fix it ticket, like no lights on a bike is.
As a word of caution here, if you are pulled over while cycling, you do not have to comply with a bag search. Don't let an officer intimate you into doing so, but try to be respectful in the process. Riding a bicycle on a sidewalk, or without a headlight, is not sufficient probable cause to believe you are carrying drugs or contraband. If this has happened to you, feel free to send me your story. I have had letters written into me about these kinds of cases, but often with no follow up on what the outcome was. Keep in touch, these stories need to be told. Although keep in mind I am not a lawyer and my advice should not be taken as official legal council.
If Santa Monica wants to ban cyclists off of sidewalks, than it ought to be prepared to defend cyclists from motorists who honk and yell at cyclists on the road. As of this time, I don't think Santa Monica has done enough to educate motorists and cyclists alike of what bicyclists rights are. As long as motorists feel they can freely harass cyclists with unnecessary and uncalled for honking and yelling, and using their horse power and engine revving to intimidate, some people will ride bicycles on the sidewalk no matter what the law has to say on the matter.
This creates obvious conflicts with pedestrians, and I myself as a pedestrian have been brushed or nearly struck by bicyclists on the sidewalk. There are also a lot of sidewalks that go unused much of the time, because zoning separations have made many places undesirable to walk in because homes and goods and services are spaced so far apart. These often empty sidewalks invite cyclists afraid to ride in the street, and very little effort is made on the part of the city to inform people that sidewalk riding is in fact illegal. West Hollywood at least puts up signage informing cyclists that sidewalk riding is prohibited in certain places, and those places all have bike lanes adjacent.
On the flip side of this, in Santa Monica we have almost as many pedestrians on the bicycle only portions of the beach path as we do cyclists. Does the SMPD patrol the beach path and issue citations to pedestrians blocking the flow of bike traffic, followed by searching their bags for drugs? If so I had trouble finding any such stories. Many cities are rife with double standards in their treatment of cyclists, and Santa Monica is no exception.