Hmm I would not trust this ad from ebay. Ebay has a long history of making money off and allowing for criminals to keep selling fakes, just look at all the horrific stuff in our "is this fake watch real?" thread...
Can someone read the terms and conditions? Would be interesting to hear what happens if you buy a "good" fake that these "third party authenticator experts" confirms as real. Or did I miss that part in the ad?
Also, who pays for this? Is it the seller who pays a higher sales fee to ebay? Nothing in life is free and I would never trust a free authentication service that quickly looks at a watch to confirm its real or not...