Well one would assume a store policy isn't exclusive to just a few local stores, especially when said business is available all over the place.
Last time I checked, Gamestop doesn't even give you cash for trading in games - they give you store credit. To go towards other purchases.
But whatever, it's Muslim's loss. Especially when the Store Mode DLC rolls out. Who gives a stuff if he's getting rid of it? It's his decision.