[ggchappell]

I don't see why the reasoning didn't go like the following.

California law requires the property owner to give up rights. The eminent-domain laws require the state to compensate property owners when forcing them to give up rights.

Conclusion: The property owner must allow beach access to the public, and the state must pay the property owner for allowing this.

EDIT: The comment by gojomo would seem to explain this.

[ChuckMcM]

Yup, the question is whether or not the treaty trumps California law otherwise it would have worked exactly that way.

I like the idea of working out a 'patch' to the treaty, although I don't think I've heard of that ever happening in practice, new treaties yes, but patching an old one not so much.

[ballard]

Adverse possession may be used to force an easement on the grounds that the access road was itself de-facto public. If not an easement maybe forced in any case.