That's my thought as well. The reason I asked is when D moved BTN, it listed the change in the guide. With the alternates, they just disappeared without a "moving to channel XYZ" notice.
Used to be 218(-1) and 219(-1). Did DirecTV get rid of them or just moved them elsewhere?
Granted, these channels show a black screen for 350 days a year, but it would be nice to see all of the football games BTN offers on Saturdays...