Look ... when I buy a product, I expect it to come in its original packaging straight from the factory. When its out of its packaging, I have no idea where the product has been. Sure, it could have been safely stowed in drawer, but seeing the assholes who work at my local gamestop, I can only assume the game has been used as a coaster for a cigarette stuffed bottle of stale miller light. How am I to know otherwise?
Because, if it's not sealed in its original case, you can look at it, you know, with your eyes, and then choose not to buy it if it's scratched or if there are tracces of cigarette ash or beer stains on it. Or you can tell the manager that you want one that wasn't a "display copy" and if they only have "display copies", then you can either buy it, or not buy it, or try to Intimidate the manager, or just wander around and level up for a while and collect more gil, or whatever. It's really up to you. But let's dispense with the drama. It's not like the store is replacing the sticker on the top of the case (that's such a pain to remove) and then re-plastic wrapping it and pretending that it's never been opened. Sheesh.