That item in the Bakersfield paper sounds like a land owner really ticked about illegal motorcycle access. Those concrete cylinders with spikes would make a good tire puncture.
As for KevinR's civil war comment: Everyone loses when a war starts. There may be a winner, but you can be sure there are huge losses on both sides. I think the entire country lost that one.
As for the open carry situation in California:
San Diego assemblywoman Lori Saldana has submitted a bill, Assembly Bill 1934, which would ban open carrying in California. The bill has passed the Committee on Public Safety, and is supported by the California Police Chiefs Association.
It will be interesting to see how that bill goes. I am sure we haven't heard the end of it.
As for people open-carrying in national parks: There just aren't that many people who do that anywhere, and I think somehow, the profile of people who go to visit national parks does not intersect very will with the profile of the open-carry group. So I don't think we will ever see much of that in any national parks.