They don't always refuse - see my personal story above. We didn't have to argue with them at all; actually, they are the ones who suggested replacing our TV. We would have been happy just to have the HDMI input replaced with a used part. I'm really happy with the service we received, and I love the TV we ended up getting. It's much nicer than the one it replaced.
Just out of curiosity, how long ago was that? If it's been a while you'll find things at BB have changed. They USED to have great service, these days it's just horrible. If this happened to you recently, all I can say is you are one of the very rare lucky ones. Seriously, you are the ONLY person I've encountered that A) got something covered and B) didn't have a total run around while trying to get something repaired. I'm happy it worked out for you, but you are the exception and not the rule.
It wasn't just DH and I, he has several co-workers that got warrenties on computers they bought. When they had issues, BB claimed that it was virus related and thus not covered. When they all paid out of pocket to have someone fix it, every single time it was a hardware issue, and nothing to do with a virus. So, thee co-workers, DH and myself, and tons of people online...this isn't just an isolated incident, this is a pattern of willful deception and fraud, as far as I'm concerned.
But don't take my word for it, this thread has at least 14 pages worth of complaints related to their so-called warrenty:
http://www.consumeraffairs.com/retail/bestbuy_exwars.html
If people want to shop at BB, that's fine. Sometimes they're the only game in town. But they ripped us off to the tune of $1100, so I certainly won't be. But I will always warn people that if they do decide to shop at BB, they should at least do themselves a favor and not buy the warrenty.