YES seems to be very litigious. After their long drawn out brawl with Cablevision, they are now suing Time-Warner. They don't want to make their channel "optional", they want to ram it down every one's TV. http://wcbs880.com/yankees/yankees_story_242083227.html
It's quite a difference for YES to get money for every cable subscriber, or get money from only those who request and pay extra, maybe 10-20%.