It is a sneaky way of limiting their liability. But it doesn't stop there.
I've also found that EVGA doesn't make any effort to fix the serial number sticker to the card. Without this sticker, the warranty is void. They stick the sticker randomly on the board, on top of pins or other surface mount components, and the adhesive itself is weak and it easily falls off. I bought a GTX 560 a couple of months ago and have used it for testing several rigs, and even though I knew the sticker wasn't well fixed, I wasn't careful enough; it fell off without me noticing, and is lost; now I have an unwarrantied card, even though I'm the original owner.
Funny how the price sticker from Microcenter is near impossible to remove from the package but EVGA's warranty stickers fall off on their own -- wonder why?