I had an original iPad with a single dead pixel and went to an Apple store and got a replacement. They did ask where I bought it from, I guess it didn't matter to them much? Just ask 🙂
went to cerritos apple store, showed them a dead pixel in the middle of my ipad2 display and "genius" said they wouldn't replace it but if it bothers you alot, we'll return it for you. never going to that apple store again.