They do tend to extend promotions when it comes to free system promotions but when it comes to 3 free months or programming it is less likely to be extended. They always come up with an expiration date for a promotion whether or not they plan on having the promotions longer or not to get people to hurry up and get the deal.
Hopefully they will make the decision before the chat, and announce it on the chat. I'm not sure Charlie would want to make the decision live on the air, although that would add to the drama.
If the competition particularly DirecTv offers free programming then Dish would be more likely to do so as well, especially with Murdoch in charge of DirecTv.