I suspect the San Francisco Chronicle rivals the Washington Post in its anti-gun and anti-law enforcement bias. That said, given the workload of most agencies, I doubt law enforcement in California is attempting to backdoor a gun ban through red flag confiscations. Given the number of people we encounter who really shouldn't have guns (and probably should be institutionalized). those numbers don't seem excessive.
I think the real abuse of red flag laws will be by significant others, parents, children, and to a lesser extent co-workers and neighbors.