Has Netflix done live video on anything approaching this scale? I don't doubt that they have the capabilities to put a live streaming infrastructure together for something like this, but DTV's out starting next year and there's a lot of work to get done in that time. That would be a lot of risk.
At its peak, Netflix accounts for something like a full third of internet traffic in the US (almost double Youtube's haul).
Live steaming is a whole new ballgame and something Netflix has never tried. YouTube has live streamed many events such as Google IO and Presidential debates.
It would be interesting to see if Netflix's architecture is even capable of supporting NFL Sunday Ticket.