Re: Personally...
The boundaries of his property were set when Mexico owned Upper California and he is relying on article X of the Treaty of Guadalupe Hidalgo, which guaranteed the protection of Mexican land grants. Unfortunately for him, the US Senate deleted article X before ratifying the treaty. This along with later legislation guarantying right of way to public beaches means, yeah, he's being a dick.
http://www.archives.gov/education/lessons/guadalupe-hidalgo/
Biting the hand that feeds IT
