Most receiver models do this automatically. I do not know why they would make it a choice with the 811. They probably think that people wouldn't want them down there because of OTA locals. But, since the OTA locals have no program info, it's necessary to have the Dish locals down there, just to know what is on the OTA locals.
It brings up the point once again that DirecTV manages the Hurculean feat of local OTA program info. Why can't Dish? Perhaps, when it comes to the 921 (someday in some future update), they'll be able to port it to the 811? Yeah. Someday, the Red Sox will win the World Series, too.