I think the main reason is promos. First off, radio broadcasts suck since they spend a good 30% of the time presenting you the subway 3rd down of the game followed by a Meineke sack and a KMart punt. At the same time, TV broadcasters promote shows coming up on Fox/CBS, and that is why they pay so much money for the rights to the games. If it were to be done, the networks would demand that customers pay a huge fee for the right, to discourage widespread distribution and offset potential ad decreases. That sounds right. Although.......for the amount of money we fork out for NFLST, one would think it buys a little leeway on that type of thing. The networks would rather everybody just watch the one game broadcasted in their area. They don't want you flipping channels. Obviously. That's why we pay big bucks.....to override their wishes :)