Why would you need a proof of purchase? Intel can verify that it's its own unpatched chip out in the wild being returned for a recall. It doesn't matter if it's the original owner or a woman 15 owners down the line, it's still a loose security flaw out in the wild; who knows where or who whose network it will wind up. I don't need a proof of purchase when I bring my Ford in for its 10 recalls a year. I don't even need to care about which dealer I bring it into. It has to be fixed. They look at the VIN and if it's not marked as fixed they fix it.

Is there a market of 99%+ seemingly authentic fake Intel chips out there?