Unless you make a habit of only buying with cash at gun shows. Even if you order online, if you have ONE registered AR-15, how can they know how many UNREGISTERED AR-15s you have?
They know.
If they want our guns, they will knock on the door and demand them. Hand them “the one” and they will just burn your house down cause they know you are lying.
The next guy will give up ALL of his guns, 80% or not.
This is what the Nazis did and it was very effective. In case you missed it, our government is using both Hitler’s and Stalin’s playbook these days.