Yes, the customers will shoot those dealers after they find out that their MS/PR 70 coins are basically worthless.
It seems to me that the FTC should step in and stop wnat is an obvious deceptive grading process. If a coin is graded, whicn is subjective anyway, as a PF70 you already have the hignest grade available. All these labels are gimmicks to get you to pay more for the same quality coin. The only reason to pay extra is if the label makes the coin more mysteriously interesting, just like wrapping paper for a gift.
Years back, proof coins used to be gorgeous for the first few coins, then the dies would wear, and the rest would lack that cameo frosted look. For lack of a better description, they were called first strikes, early strikes, etc Mint methods have improved, and you can expect your proofs to all be gorgeous. But the words remain. Even newbies realize that it seems to add some cachet. But, its just words. Like ALL NEW! IMPROVED! LONGER, LOWER, WIDER, WITH MORE ROAD HUGGING WEIGHT! People need to be educated.