This would work assuming the governing and policing system is to be trusted. The reason fire arms purchased with the intent for self defense already demonstrates you don’t.
Not to mention the possibility someone dupes a firearms ID and negates the system.
The idea that you need to buy a fire weapon to self defense against hypothetical encounter with a bad policeman is plain stupid. Do you know what really could help for self-defense against police? A good lawyer. A pistol will just grant that you will die like a dog for no reason.
So after the hypothetical policeman is done doing some hypothetical wrong doing ( assault and the other one ) then I should call my lawyer? There’s more than just the scenario of a policeman writing a ticket that I can dispute with the judge.
Not to mention the possibility someone dupes a firearms ID and negates the system.