Some users are beginning to realize that iTunes Store Movie Rentals may not be compatible with their iPods (via Wired).
While Apple does state in its movie rental FAQ that a "iPhone, iPod touch, iPod classic, or iPod nano (3rd generation)" is required for mobile movie rental access, other more prominent references only mention "iPhone or iPod." This distinction has left users of video-capable fifth generation iPods without the capability to play the files, though they can play purchased movies, TV shows, and compatible podcasts.
Similarly, it was noted early on by Engadget that Apple's HD movie rentals were only accessible to the forthcoming Apple TV Take 2, and would not be transferable to a computer or portable device.
