Can't all of this be avoided by the companies implementing a simple rule?
The most vomit-inducing buzzword of the last few years has to be "comps". Well, make the customer cite X number of recent hammer prices for what grade they feel the card should be getting. This can then be cross-referenced for accuracy. Yes, that's a very time-consuming task, but someone on each company's end is clearly already spending time ascribing values in one manner or another.
If anything, one could assume that this may end up
saving some customers money (on their submissions, anyway) when their delusions of grade grandeur result in a refund due to the TPA disagreeing that their cards truly aren't that minty fresh to accurately correspond with the referenced comps!
(Of course, nothing this simple would ever work out. It was written as a joke more than anything.)