I don't know if this has been posted before but it's worth posting again. The two links are to the investigative news reports that were put out by 20/20 and NBC. What brings it back to me was the recent newsletter we received from the Traffic Investigators Association in Michigan which has an article where a member had the problem and was able to receive a full refund on tires that were 10 years old when purchased. Tires need to be used to keep their pliability or the rubber compund breaks down, just like any other rubber product.
http://www.msnbc.msn.com/id/24390155/
http://abcnews.go.com/Video/playerIndex?id=4826897
Hopefully these come through as a link.