The only real problem with OC'ing it is newb's dont set it to a lower setting at idle, or when charging. Leaving it at 1200Mhz all the time is asking for trouble.
Then you have the typical ones who push it a bit too far, but that just involves lowering it slightly.
I also really can't see the store figuring out what has happened, they are going to see if they can ressurect it, and when that fails, they'll give you a story like the display burnt out, not knowing that you may know more than they do on it.
Exactly what she said lol.