What does it mean when Gamestop does "identical exchanges" with opened merchandise?

“Identical exchanges” means that, if you have opened the package and taken the item out of the box, you can only swap the product you have bought and are now returning for another that is exactly the same (same make, model, etc.). In other words, you can only return a product that is faulty or damaged in some way.

Such a policy is to dissuade people from abusing the exchange and refund policy by, for example, taking a product home to try out and then deciding to swap up to a superior product, or buying a product, using it over a weekend and then returning it. Such activity is costly for a merchandiser. It is also fraud.