Perspective from the PRK
I live in the People's Republik of California, and I don't even worry about it that much.
Way back in the day, long before California came up with mandatory registration of all firearms transactions, I bought and sold MANY guns. A few were even voluntarily registered, and some were purchased new, and registered that way. Most were sold LONG before the requirement for sellers to complete a transaction through a licensed dealer. I have no doubt that there are at least a dozen guns out there, which are registered to me, but I haven't owned for 20+ years, simply because up until the 1990's, The PRK did not require registration upon transfer. I likely still have many guns that were never registered, because I acquired them long before then, but even more that ARE registered to me, because of the change in the law, and that I now buy most of my guns new, anyway.
As a retired LEO, with an HR 218 cert., I have no concern, that the state will deem me, as having "too many" guns, and come looking for me, even when "The Big One" hits The PRK. It's just a non-issue. That's saying something, when you live in this much of a socialist state.
That all said, I am in process of moving to a state with far more firearms freedom, than any other, this side of Vermont, and it will all be a moot point, at that time.