I think it was the MPAA that tried to develop DVD players with cameras so they could count room occupancy and lock the content if you were tying to exceed the terms of their license.
Please drink verification can.
(This never happened though. The MPAA did a lot of shady things with DRM, but not this.)
I believe this was a Microsoft patent related to the kinect.
Was it Sony that had the patent on a device that would require the watcher to say the product name out loud to the microphone to continue watching? The product to my knowledge doesn't exist but the patent for it did.