California just did the nasty letter thing for close to 20 years and even then, the only door to door stuff was against those who had previously been legal and registered their guns, then became "prohibited persons" at some point later.
In the three to five years prior to going after the "prohibited persons", they did a rework of the law enforcement exemptions to the gun laws. In fact in 2004 and 2005 I was in California gun shops which had "all the cool stuff", but it was behind a roped off area for law enforcement only. The exemptions were broad enough that anyone with any sort of law enforcement status, or even former status could wheedle in under the exemptions.
Hate to sound like a hypocrite about it too, but even when I trained at a law enforcement academy there under contract with a State Department contractor, we had the exemption which made my previously registered AWs nothing special when I thought they were. What I saw though, were cops who were training at the same facility who had gone from out of state and had obvious postban ARs. When I asked about the legal status on that, I was given the "fuck you and you are rude for asking". Later in the training cycle, some Homeland Security guy from Oregon showed up, tried to be casual about asking the same questions, and they pointed at me, as if "we answered your buddy motherfucker and don't ask".
At about that stage, I was on a few shitlists, but not all of them, so it was me who ended up explaining "the score" to the guy who had scrounged up 10 shot mags to do his portion of the training cycle since he had traveled from out of state.
Old rules, only your duty weapon could be non compliant, and you had to have paperwork or something to prove that any particular firearm was your duty weapon. Have restricted mags for a non-duty weapon, then you are in trouble.
New rules, its like if you are cool with anything law enforcement, then it does not apply.
I bring this up, because that's apparently how things worked with the recent ISIS sympathizers. Private party sales of firearms has been illegal in California for over 20 years, long guns, hand guns, don't matter, and they don't even approve the sale of restricted assaultweapons on most probate situations. If someone dies, the family can strip the gun for parts or ship it out of state, but when the owner dies, that goes away from California or it is contraband.
I also don't get Dorner's guns either. When he was kicked out of LAPD, his exemptions were over, although I would guess that he was benefitting from a bit of "professional courtesy" since they knew he got kicked out of LAPD for illegitimate reasons, and if they pushed him it might be a whisleblower lawsuit (as it was, they got a whistleblower shooting spree which I am not entirely sympathetic or unsympathetic about since I had no dog in that fight).
