Several times a second the OS will check all the hardware to makes sure it is in compliance with the HD encryption standard. It will look at the video card and display and other parts too It will also phone home to ask for a key to start playing.
It would vary easy to track every movie watched in the world at any given time.
The battle over the encryption schemes has delayed HD for years.
You put your disk in to play a movie it checks all the hardware even checks to make sure you don't have two LCD plugged in and if everything is OK then it will phone home to ask if it is OK for you to watch the movie. I’m sure this will never be abused. S/C
Thank you!