What I meant is that they have no other choice if they actually want to enforce this law.
Sure, they could go to the door of everyone they suspect of having one of these weapons, based on their records, and demand entry or surrender...but only a complete fool or idiot would accede.
They cannot obtain a warrant based on those background check records.
Now, what I personally would like to see is 10,000 of these rifle owners rally, with their weapons, on the Capitol Steps...taunting LEO, Elected officials and media.
They just better make sure these weapons are loaded.
There are probably 10,000 of these rifle owners or many, many more who have owned them way before they needed papers to own them.