>  if we want to demand that an electronic media
  > purchase is a traditional sale

Were these ebooks really treated as traditional sales? While we might want to get to a place where they are, if they are currently not treated as such, then why shouldn't we get the supposed benefits of the current model? If part of the agreement terms of the purchase are that you can download from B&N indefinitely once you purchase the ebook, then they should honor that, regardless of the state of your credit card.