1. We're going away from hardware mixing by default, so the problem becomes far smaller.
2. Nobody is claiming that this is what `outputs` in MPD are intended for. It's just a convenient way to toggle flags in Mopidy through MPD. Coincidentally, muting an audio output is quite close to Mopidy stopping its usage of an audio output.
3. I've never seen a client disabling/enabling outputs through MPD automatically or as a side effect of something else. In all clients I've seen, it's a separate menu choice.

That said, we could probably consider renaming the output from `Default` to something else, though I'm not sure exactly what.