Just a thought, but thinking it might be a useful feature to be able to go into Settings for a Sonos Room and disable playback of certain sources (streaming service, TV, aux line in). 

So for example, if you a home theatre room where you never intend to play anything but TV audio (perhaps because you have other Sonos speakers setup in the same physical room), you can disable all the stream services for that room.  You would not be able to start a stream from this room or join an existing group.   Another use case would be if you have a guest room where you want to allow use of certain streaming sources, but block others and perhaps your local library.  Or perhaps you have a kids room where you only want them to use their own streaming account.  It also could be useful if you have a Connect/Port with no amp attached, that’s only used as a line in source.

I can understand where Sonos would not want to limit a system’s capabilities, but this sort of thing could be helpful in getting a system ‘dialed in’ to what a customer wants.  It wouldn’t necessarily need to secure under password, but hopefully just prevent accidental groups/playback for rooms you would never want a source played.