Tried it at three different Gamestops and succeeded in all three locations, multiple times. If you're worried about being rejected, make sure you talk to the manager and say something like "My (insert relationship like little brother)'s birthday is coming up and he wants X game, which I found in Y location..."
It's a victimless little white lie, IMO. That's how I got my Suikoden II, Rez, and Gitaroo Man before the last two had a reprint and saved loads of money.