Ex-world champion Vladimir Kramnik–whose opinions I have always found the most common-sense and fair-play amongst the elite–fully supports the decision by the Moscow Candidates tournament to limit other sites from the LIVE transmission of the games.
No doubt others have different opinions. As far as I understand, the legal issue of copyright is NOT clear, and might vary from country to country. Certainly the Candidates’ organizers have rights with respect to live video feeds, but court decisions in the past have made a distinction between the transmission of the moves themselves and the actual transmission (video) of the game being played. That is why analogies with Tennis and Football television transmission fail in legal challenges: a pgn-file of a chess game is NOT the game being played (only a record of the moves played in said game).
My own view is that the Moscow organizers should not restrict other sites from transmitting the moves as they are played. That being said, I await with interest the outcome of some legal actions taken on behalf of the Moscow organizers. Certainly the chess world will be a very different place from what we have grown accustomed to should the organizer’s position be found to have legal basis.