There is a thread on another coin forum about a PCGS PR 70 DCAM Roosevelt Dime currently on auction at
Heritage. The original poster questions if it really is deep cameo. Another fellow replies that the same coin has slightly better photos in an older auction:
http://coins.ha.com/common/view_item.php?Sale_No=438&Lot_No=846.
The OP was right to question the grade. When you pay big bucks to purchase the finest known it really ought to be the finest known. Some people replied, correctly, that the photos were poor and you really need to view the auction lot in person before bidding on that coin.
There were several other people who said something along the lines of "since PCGS certified it you don't need to look at it, for sure it is a 70 and a deep cameo." These people "drank too much Koolaide"and need to wake up and look at the coin. Close inspection of the photos reveal a strike through in the torch's flame. A coin that wasn't perfectly made does not deserve the grade of 70.
PCGS is good, probably the best, coin certification service. However they make mistakes. They seem to make the most mistakes with the grade of 70. I personally purchased 9 Jefferson nickels in the grade of PR 70 DCAM. On close inspection 4 or 5 of them were not 70s. I returned 4 of them for grade review and all were downgraded. PCGS lived up to their guarantee and I was happy with the result. They kept 3 of the coins but returned the worse one in a brand new PR 67 DCAM holder! Now how did a PR 67 ever get into a PR 70 holder?
So when spending more than a trivial amount of money you should grade the coin yourself. Decide what it is worth. Then look at the holder and price to see if there is a match.