I'll have to admit that this happens at Rhino, too. Aside from the one display copy (which must be opened, there's no two ways about this), if a customer exchanges a new game within the 7 day window, it's placed back on the shelf as new. Yes, it's been handled. Yes, it's most likely seen the inside of a console. When it's returned by the first owner, we always investigated the disk, case and manuals to make sure it was still in mint condition. Any flaw whatsoever, that includes even bending the front page of the manual, meant that we could not exchange it back as new (though we'd be happy to do so as used, usually $10 less). Whether the other stores were as strict, though, I can't say. We also warned customers when they bought the games to keep them in mint condition if they thought they wanted to exachange it, so we never really had anyone argue the point.
It might sound crappy, especially to the hardcore game afficionados (of which I am one) but it was a small price to pay to allow the whole exchange thing in the first place. And if asked nicely, we would have been happy to either hunt down a sealed one, or pull one aside for you when more come in.
Honestly, the ratio of people who complained about buying an opened "new" game versus the people who complimented the exchange policy was like 1:100.
But GS has no real excuse. There were also other things about GS's methods that we hated, especially all their damn stickers. God how I hate their stickers! I got pretty good at removing them, though.