it sounds like you have autoplay turned on.  if you don’t want the Five to play whatever is on the line-in when it senses audio, then turn off autoplay in the settings for that room.

As far as your suggestion that the Five should resume a stream after you no longer are using the line in, that would get rather compicated.  TheSonos speakers don’t retain a history of what was previously streamed liked that, where they can go back to a previous stream.  It only retains what’s currently playing, or what was playing before payback was paused/terminated.  In your cases, that’s the line in source, not the stream that was playing before line in. 

The line in connection wasn’t really put there so that a Five could double as a computer speaker. but so it could be used with auxillary music sources, like a turntable.

Thanks for replying. I do understand how Autoplay works presently, I’m using it.

Doesn’t seem like it should be a huge leap to retain the state of the stream before switching, and restore it. If the speaker can’t store that, then it could interrogate the most recent controller. It would be a little work in the software, but I can’t see why it couldn’t be done.

This would be a nice feature for people who work at a computer all day, and there are lots of us.