Are this person's initials JCN, by chance?
Sticker on a case = annoying but nothing you can do
Sticker on a disc = UNPLAYABLE IMO - this is a hotly debated goozex topic. But at the end of the day, the only workaround for those of us who don't want gamestop style, stickered discs or heavily used discs is to simply not have as many requests.
So I simply request less as I don't like spending points on crap condition games. I can't do anything to stop someone sending me a dirty manual and a scuffed disc w/ schmegma on it, other than simply not requesting it at all.
Two words: Goo Gone.
kittybooty: Two words: Goo Gone.
Two more words: Love it.
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GreenManGaming
As everyone has said already, a sticker on the case is not grounds for negative feedback. I think it's a bit of an abuse to even leave a +5 if that's the only thing "wrong" with the game, but people's opinions may differ on that.
The best thing to do is just remove any GameStop stickers from the case. I've found using a hair dryer makes it very easy to do, and I don't end up leaving bits of the paper part of the sticker on the case then.