Most settings are inaccessible unless logged in. You need to reset the app (in App Preferences). Then connect to existing system and try to change some settings (without logging in)

Cheers John, makes me feel a bit more comfortable.

To be fair, the worst that has happened so far was someone creating a stereo pair with 2 speakers in different rooms! - but I just want to give guests a good experience without risk of cockup - either accidental or deliberate 

Hi. To pick up on your particular example.... Once you have reset the app on a particular device  and reconnected to the system, it won't be possible to create a stereo pair without logging in. Which they can't do without knowing the Sonos account password. 

So to achieve this I only need to reset one device, and this will prevent it on all devices ?

The controller is merely a “window” to what’s running on the speakers. There’s no inherent “smarts” in the controller. 

Yes, it should work when you set it with one device, and carry over to all other devices that connect to the same system. 

Sorry I disagree with Bruce on this one - a very rare event indeed. Each app that you want to be kept out of key settings needs to be reset.

Well I reset one device, then tried to set a stereo pair on it, and I was given a login prompt.

will try on the others before a reset and see what happens and give feedback 

I can confirm that when logged out, none of the controllers allow me to set up a stereo pair without a login prompt after resetting one controller.

Sorry but that is not a robust experiment unless you checked that you weren't given a login prompt on the other apps before you reset the first one. 

I suggest you log into all controllers then reset just one and see what happens. 

I have just realised that you said the other controllers were logged out. That is what has protected the settings, not resetting one controller. 

The reset is just a means of logging out.

 if I reset just one controller whilst logged in to all of them. I will still be logged in on the others.

I’m not trying to prove or disprove a theory, I honestly can’t say for certain that one controller wasn’t logged in when the stereo pair was set up, all I want to do is be confident that when logged out, a user cannot screw it up.

Ok, I think you have answered the initial question, having reset a controller and being logged out on all of them, a user shouldn’t be able to mess things up.

Logging out and reset accomplish the same thing for your purposes.  Device by device. Users will always screw things up but there are at least some restrictions. 

I’d agree, it’s rare for John and I to disagree….but he’s got more knowledge than I do, at the end of the day. I trust his depth of knowledge implicitly. And this isn’t something I’ve done much of, since I live alone. 

However, the key thing is, if you now grant access via wifi to a friend, who’s setting up the app for the first time, they’ll not have access to those settings.

Thank you both for your input, much appreciated