Without a concealed carry permit, any law-abiding citizen who travels with firearms in California must keep them unloaded and in a locked container [0].
It used to be incredibly difficult (nearly impossible [1]) for regular citizens to obtain a concealed carry permit in San Francisco because they had a "Good Cause Requirement" which essentially meant that your cause was not good enough.
Apparently, that changed in June of 2022 with a recent Supreme Court Ruling [2].
There are also [3] many stories of victims who shoot their attackers either being prosecuted criminally or sued for civil damages.
Lastly, while the views on concealed carry vary widely throughout the US, most social environments that I ever encountered in Northern California would find it repugnant.
[0] https://oag.ca.gov/firearms/travel
[1] https://www.desertsun.com/story/news/nation/california/2022/...
[2] https://www.sanfranciscopolice.org/get-service/carrying-conc...
[3] Oregon, not CA https://www.gilmanbedigian.com/man-who-shot-intruder-in-his-...