I don't want any law passed that makes is easier to accept stolen goods. Next time, check the damned serial number on your used gun purchase yourself with the police.
Garretson's sold me a hot gun!
Loosely translated, you bought a hot gun.
The law already requires merchants regularly dealing in goods of the kind warrant that such goods be delivered free of any rightful claims by a third party.
You're flipping the burden here--merchants are simply in a better position to ensure the goods that they sell aren't stolen. It's just better policy.