I seen no problem with this, either.
It's the purchaser's responsibility not to lose his book and it is his decision to download it when he buys it.
If an author comes out with a new edition, is the author then required to give you the revised edition?
If an author decides to withdraw a book, is the author obligated to give you a smiley face and a pat on the back and commiserate with you because you didn't download the thing you bought?
If one was smart enough to download the darn thing that was purchased, then what's the issue here?
I would say this is a non-issue, and is the responsibility of the buyer to keep up with his or her purchases.
BUT WAIT! 
-- There's more: Stephen King owes me the revised edition of 'The Stand', because in 1978 I purchased the original one in hardback.
