> The format does not make it irrevocable, it makes the revocation impossible to enforce.

Fair point and I should have used less ambiguous terms. I'm also thinking about the "Permitted for Home Use Only" nature of DVDs. Playing DVDs on a projector for profit (assuming no prior permission) is, of course, a breach of their protected rights no different than those who re-stream live sports over IPTV.

It's easy to get caught in the details so I think it's useful to remind ourselves that "Intellectual Property" is fundamentally a temporary legal protection and that everything released to the public becomes public domain eventually, either de jure after N years or de facto (ie. "abandonware").