Well, as this is similar to something I had suggested
earlier, I can see a way to implement such a thing that wouldn't be a complete finger in the eye of the customer.
But it would absolutely
have to not expire my content.
I suspect they're only selling PD stuff right now because they haven't gotten buy-in from any actual
publishers yet.
While I don't think they'll get many takers on selling PD stuff, all they're really selling is the reader software and the physical packaging -- pbooks don't have "reader software," but you still have to pay Barnes & Noble for the packaging when you pick up a copy of
Round the World.... there.