How about integrating the Google Voice Interaction API or Apple Siri to control Sonos (Apps)?
My favorite handfree scenario: Cooking, both hands occupied, no music. As I have an Android device with "OK Google" on all screens activated, I'd love to say something like "OK Google, start Sonos in Kitchen" and it starts playing the recent playlist.
Should be similar with "Hey Siri"...
What do you think?