They'd likely end up receiving a SLAPP by Khosla, but surely there would be some judgement-proof surfer willing to shoulder the long tail risk, and plenty of people willing to pay for the legal defense.
In the meantime, California has been end-running around the whole right-of-way issue. It's been saying "whether or not there is a public right of way, you need a permit to put up obstructions."
This has worked insofar as Khosla has not actually applied for a permit yet. But at some point the State will have to justify denying Khosla a permit, and asserting "we're going to do through our fence-permitting powers what we cannot do as a matter of property law" is not a great look.
Those people willing to pay legal defense are called the Surfrider Foundation and they're the people that keep suing Khosla to open up the beach.
It's been quite an ordeal.
I assume you mean the police did?
Don't trust anyone when it comes to people with "fuck you" money.
Not trusting people with money (regardless if it's a lot) says something about society in general. People should understand that even amongst the rich, people are very different and diverse despite being in the same socioeconomic class.
No, for the same reasons you can't demolish your neighbor's house the instant you found out the surveying was done wrong and it's on your property. There's a lengthy legal process involved before you get to do that.
Cutting the lock would be destruction of someone else's property. Their actions are a separate legal issue.