I would like to suggest a change that would preserve the audio output zone even if Roon cannot find the device on the network or connected, especially if the zone has been used recently and there is a queue of songs that have not been played yet.
The played ones I can see in the History, but the ones which have not been played yet, those are gone forever.
It happened to me that I sold my streamer and forgot to transfer my extensive queue of about 200 songs, which I wanted to listen to, but since my device was no longer on the network, nor could I reconnect it, I lost the entire queue of songs.
I hope it makes sense the way I explained it. 
Thank you