Isn't the purpose for the 'download to hard drive' because of the immediate switching between TV, games and/or movies? That option wouldn't work effectively if the system had to boot a disc every time the player switched options.
And if that is indeed the case, it's understandable why the system would want an online check to verify the content, else people would just download and then sell the disc for money. The system (gaming) would absolutely break under those conditions.
And really, PC fans who love Steam should have no issue with this, and since this is GAF, the environment for gamers, you could safely assume most folks utilize Steam.
So again, given the abilities the system provides, there has to be an online check at some interval.