There was a thread here about a week ago where someone photomatched their Pelle Lindbergh super pad, and John came out and said that when he was able to track the winners of those auctions, he knew it was Brian Price. Price's acquisitions in a whole have been pretty public, and he strikes me as the kind of guy that would keep a paper trail of all of his rare purchases (tax purposes? Wouldn't these be business expenses technically?)
I have little to no doubt about the authenticity of what we've seen in the ITG products thus far, especially with the emblems/numbers. All of them can be linked back to a previous ITG product where pieces may have been used (like old all star jerseys and such) and there's nothing out of the ordinary that I've seen so far.
That was me with the Lindbergh pads, it was very interesting to trace the memorabilia back a bit and as a result I value my collection pieces more.
When it comes down to it the authenticity of memorabilia cards it's all about trust. Tracing the Lindbergh pads to a
potential match on Classic Auctions (I am not 100% positive they are the pads, but I am very confident based on what I found and what John said) was one step of the process, tracing that auction to a reliable source is another step that needs to be considered. In the case of the pads the auction stated they came from the Lindbergh family, that's where the credibility of Classic Auctions needs to be taken into account and I feel they are a reputable source.
In reality unless you are there to personally witness the player using the jersey, handing it to you after the game, travel to a manufacturing facility with the jersey on your lap, cut it up by hand, apply it to a card, and place it in a pack yourself there is rarely 100% certainty of the source of a jersey. Even if you DID do all that yourself, you still need the next guy to believe that your experience was true or it was all for nothing.
If Dr. Price is anything like me, he would not even lay eyes on a piece of memorabilia without being certain it is coming from a trustworthy source. I know he is a collector, I know he is very careful when seeking out memorabilia, and I trust that it is authentic. Upper Deck on the other hand, who knows where they are getting their memorabilia? You see the odd Meigray tag piece in a card from time to time, other than that it could come from anywhere and there is nobody stepping up to stand behind the authenticity.
I do have a couple of UD memorabilia cards in my collection, but I don't place the same sentimental value on them as I do with my ITG cards because I frankly don't trust the authenticity of UD game-used anymore.