What confuses me is why they don't just continue broadcasting Sporting News, but at the same lowered "traffic & weather" / AMBE(r) codec low level of bandwidth that the loop "Sporting News is not available right now" gets?
(IMO, if XM was truly concerned about bandwidth, they'd have one generic AMBE(r) codec low-bandwidth loop that said "This channel is currently not in service." or something similar. But instead, they give each out of service channel or each channel group (for ACC, MLB, etc) its own such channel. I don't see why they couldn't just remap all out of service channels to one. Even on Bloomberg, this irritates me. If you have the bandwidth to send out a loop advertising what's on Bloomberg during evenings & overnights, then just send me the real channel. Compress it to death with the AMBE(r) codec during evenings/overnights, sure - they aren't prime listening hours.)
Now, if there are contracts with partners that mandate a certain audio quality, I could see just turning off a channel in favor of a low-bandwidth loop, but for in-house XM produced content, that can't be an explanation. XM also obviously has no problem with providing some services (Canada 360 comes to mind) at the AMBE(r) level of quality all day long.