In my experience, just being on a different WiFi “logs” me in to a different system. But since the playlist and streaming sources data aren’t  stored on the controller, but on the speakers, I don’t have access to ‘my’ data. Which means I need to provide the streaming data to the new location and use non-Sonos playlists. Then I have to trust others on that ‘other’ system not to make changes. That part isn’t an issue for me, if I’m given enough trust to access their Sonos, I can trust them not to mess with my streaming data.