"User ID kept private" auctions appear to be primarily used in coin auctions to keep anyone from letting auction participants know the offered coins are fakes, or bogusly graded. they may also be a cover for shill bidding. unless you are certain that the seller is completely legitimate, don't get involved with such auctions. as for bogus grading - anything graded by GALLERY GRADING COMPANY is a rip off - graded by the seller. not an impartial 3rd party. as for fakes - if the seller is in china you can bet the offered coins are fakes. good auctions, and good sellers, have nothing to hide!