I have just been faced with this with the new Sherlock Holmes Game of Shadows bluray disk. With previous triple play disks I got an iTunes code for downloading it into iTunes on my laptop from where I could synchronise it to the iPad. This new system is much more complex. You have to install the Flixster software on the laptop and set up an Ultraviolet account. Once this is done you can download the file or view it online.
To use on the iPad you need to install the Flixster app. There is no way of playing the file in iTunes. I did a manual download to my laptop via the Ultraviolet site and got the mp4 file, but it has DRM and can't be transferred to iTunes or played back with Quicktime. You have to install the Flixster app to view it and there is no standard resolution option which means the full HD file would take up 1.9GB.
My guess is that the studios are trying to encourage streaming and discourage downloading. Not ideal unless you have a good internet connection.