I guess my point is this: If something does go south and you are the last legit owner that the John Law family can find, at least one of 'em is coming to visit. Personally, I think the fastest way to get 'em out of your life is to show 'em a factual bill of sale.
Maybe I'm wrong.
I'm certainly not a lawyer.
You will lose sales of the off the grid buyer, not criminals, folks that don't think it the governments business what they own, thus reducing the value of your sale. If an off the grid buyer can get a new SW for X why buy yours at almost X if there is the paperwork involved, might as well buy the new one...