How actionable is a violation of a website term of service, like for example, YouTube's clause 4C which reads:
You agree not to access Content through any technology or means other than the video playback pages of the Service itself, the Embeddable Player, or other explicitly authorized means YouTube may designate.
In this clause YouTube is announcing that their "terms of service" require that a viewer only watch YouTube videos through the YouTube player and not through any other player that they might have.
Even aside from the issue of whether I have "agreed" implicitly to this, what possible claim could YouTube make in a court of law against a web user who viewed their videos using a non-YouTube viewer? The legal "agreement" which I never agreed to, does not even specify remedies. How would the remedy even be determined? YouTube decides, oh hey, we decided the remedy is that you owe us $100,000,000 because you watched one of videos on a non-standard viewer?
Have such TOS pronouncements ever been tested in a real court of law?