Commonsense solutions are not allowed...:o]
I've suspected that those who claim no one else could have known the content of a FReepmail is simply the occurrence you state above.
There is also the possibility of coincidence. Being mostly informed, thinking conservatives and libertarians, and being part of the FR community, it's VERY likely more than two people have had the same idea or thought simultaneously. We've all seen people duplicate another posters remarks just moments later. "Great minds...blah, blah".
BTW, why must you prove the negative when all I'm seeing elsewhere is the accusation with NO proof.