Paul P, I don't know where you stand on the use of OHV's, but I'll venture a guess that you are against the practice in your part of the desert. I would guess this is not the first time you have advised others to deny OHV access to their private property based on your view of liability law and how it must certainly be in the real world. Things aren't always as they seem. Now you see why basing your advocacy on emotion rather than research can actually make for bad policy, and can place others in dangerous circumstances.
And we also see why allowing me to cut and paste can screw up a perfectly good internet link.
From what I've seen, a property owner is the only one who can grant or deny access to their own private property. A third party can only advise others of the owner's wishes. Private property in California must be posted and/or fenced before tresspass laws will apply, per PC 602. This section of code is a wonderfully simple and concise piece, without violating the rights of anyone. The bad effects of OHV use too close to homes and residents are all contained and addressed in PC 602. All of them. They are all enforceable, but law enforcement just doesn't have the resources.
Identifying the owner of a piece of property is far more difficult than some would have us believe. Some records do not exist any longer, some are buried or mis-filed, and some are out of date. Naturally, when there is open desert range, with a mix of public and private lands, and users are already out there on existing trails, it's impossible for them to identify which land is which without signs or fences. The vast majority of fences and signs are just fine as long as they are somewhat recent. Fences may be cut and signs may be destroyed in semi-urban areas such as Juniper Flats. But in the open desert, this rarely occurs. For the most part, most of these have been in place for decades. It's provided for in PC 602.
People move to the high desert rural areas for two reasons:
1)To live peacefully and sit on the patio and watch quiet sunsets, sip mint juleps, or whatever, and to be left alone.
2) To avoid having to trailer their OHV's to the desert, and be able to ride right out of their garage into the desert and have a little fun right near home.
Both have a right to their dream. Neither has an absolute right. But both are in direct conflict with one another SOMETIMES. It's not an easy task to parse between the two without violating someone's rights. I don't envy the task of land managers in areas of encroaching civilization and urban sprawl such as Juniper Flats.