When you first acquire music iTunes Products and music video iTunes Products (collectively, iTunes Auto-Delivery Content), {snip}
As an accommodation to you, subsequent to acquiring iTunes Auto-Delivery Content and TV show iTunes Products (each, iTunes Eligible Content), you may download certain of such previously-purchased iTunes Eligible Content onto any Associated Device. Some iTunes Eligible Content that you previously purchased may not be available for subsequent download at any given time, and Apple shall have no liability to you in such event. As you may not be able to subsequently download certain previously-purchased iTunes Eligible Content, once you download an item of iTunes Eligible Content, it is your responsibility not to lose, destroy, or damage it, and you may want to back it up.