I believe HBO's reason is that they're not using MPMoviePlayerController (the default video player). It looks like the native one, but I remember seeing jaggies

I believe HBO's reason is that they're not using MPMoviePlayerController (the default video player). It looks like the native one, but I remember seeing jaggies around the icons after upgrading to the iPad Retina. If I had to guess, it would be that they have some sort of proprietary DRM going on and have their own player for it.