Put simply, my understanding is that Federal regulations do not allow a manufacturer to refuse warranty service based on failure of the purchaser to do something like send in a card. Those regulations were put in place because most manufacturers used the cards just to gather marketing information. The Feds decided that a warranty was either granted or it was not granted as part of the terms of sale and no conditions could be placed on it. In the BGE case, they have issued a limited warranty (limited in the sense that only certain components are covered and it applies only to the original purchaser. They can require that the owner show proof of purchase but not that a card be sent in to them. As an aside, many manufacturers responded to the Federal regs by providing an additional warranty benefit to those who returned the card or otherwise registered - maybe an extension or some other extra element - and that is completely legal since there is a basic warranty for everyone and an extra one in exchange for providing the marketing info.