Since Sirius-XM is now marketing the Mirge, and slightly discounting for those who take both services on a single receiver, wouldn't it make more sense to start bumping two different channels, one from Sirius and one from XM, for each single-artist infomercial? On services with so much duplication, it would encourage dual subscriptions if there were always a way to retain the missing channel.
In fact, when they get around to merging the billing systems, they could let Sirius subs add a lowest-tier alternate sub on XM called the "Rest of XM," with the SXM channels you can't hear on Sirius at any given time. And that would of course include the channels bumped by the single-artist.