canopic jug writes:
Tim Berners-Lee approved Web DRM yesterday, but W3C member organizations have two weeks to appeal. This was the controversial Digital Restrictions Management (DRM) standard for the WWW known as Encrypted Media Extensions (EME). The last opportunity to stop EME is an appeal by the Advisory Committee of the World Wide Web Consortium (W3C). An appeal would then trigger a vote from the whole Committee to make a final decision to ratify or reject EME. As an added difficulty Tim Berners-Lee heads the Advisory Committee.
Also at Techdirt and EFF. W3C's "Disposition of Comments for Encrypted Media Extensions and Director's decision".
While I suspect HDMI may do something like that, your prepostion relies on secret watermarks.