It's true - this is coming off to many people as deceptive and disingenuous because when you rent a movie you *purchase* the rental. A rental is still a purchase. If this applies only to movies purchased *to own* and specifically not to rentals, then this should be clearly mentioned everywhere. Also, if you paid for the rental then I don't see what the problem is if you decide to watch it on one of your other itunes registered devices. What difference does it make? You paid in good faith to see the movie; you should be able to view it on any one of your itunes registered devices you choose.
We were bit by this today too:
Rented movie via AppleTV.
Taking a flight tomorrow, hey lets download it to the iPad and start it so we can watch it on the plane.
Does not show up on iPad for download or even as rented.
Plug into Macbook, does not show up as rented or available there either.
Throw up hands in defeat and try to rent it again over iPad.
"You have already rented this movie - are you sure you want to rent it again?"
...sigh...so itunes *does know* we rented the move?!?!
...give up, say yes and get double ganked on the rental fee.
Maybe we missed something but could see no way to view the media anywhere but on AppleTV we purchased it on.
It's to the point we are just buying regular old books now. At least we know we can read them wherever we want, whenever we want.