As I say in all of my articles MY 1st step in the authentication process is ATTRIBUTION, but that takes time and I believe the TPGs don't have or take the time for that step, unless it is paid for by the customer.
I think your getting a raw deal, if someone is paying you for a service and your basically not doing it, by not taking the time necessary to first making sure the item is real.
If you can't attribute it, you can't authenticate it. But the number of times they screw up the first part and skip to the second part is rather small, so it's just the cost of doing business I guess. Slapping a grade on it seems like the easy part. When they slap a grade on a fake, it must be really embarrassing. And sometimes, if you look for my 1901-S 25c thread for example, it throws the rest of us for a loop. Is this an undiscovered type or die pair? They authenticated it! It must be!! Scramble around, look at 500 coins, check with all your contacts... Oh, the TPG just #$%^'d up. Nevermind. So it goes.
This statement is not true: "If you can't attribute it, you can't authenticate it." Attribution and authentication are two different things.
IMHO attribution rules out many of the latest Chinese offerings except a few of the really deceptive ones, although many of them fell out at the attribution level as well.