Translation:

Why can someone who is not on the same wifi switch on sonos from another city?

Answer:

If they’re on the same subnet, something Sonos requires, they should be able to reach the speakers. Most VPNs don’t place the connections on the same subnet. They could, I think, use the web player instead, details at https://support.sonos.com/en-us/topic/sonos-apps

Hvis de er på det samme undernet, noget Sonos kræver, burde de kunne nå højttalerne. De fleste VPN'er placerer ikke forbindelserne på det samme undernet. De kunne, tror jeg, bruge webafspilleren i stedet, detaljer på https://support.sonos.com/da-dk/topic/sonos-apps

Jeg har brug for at de IKKE kan tilgå min sonos fra en anden by eller lokation…

Translation:

I need them to NOT be able to access my sonos from another city or location…

Response:

Ah, I’m afraid that wasn’t clear from Google’s translation of your post. 

How are they accessing your system? Is it via the Sonos S1 or S2 client, on their device? Or the Sonos web client? Or Spotify Connect? Or some other way? 
 

Ah, jeg er bange for, at det ikke fremgik tydeligt af Googles oversættelse af dit indlæg. 

Hvordan får de adgang til dit system? Er det via Sonos S1- eller S2-klienten på deres enhed? Eller Sonos-webklienten? Eller Spotify Connect? Eller på en anden måde?

:) no worries….its from a mobile phone, through Spotify…

Sonos has introduced the Web Player found at play.sonos.com. I believe this will soon take the place of the PC and Mac apps. It is helpful in that if you are away from home, you can still control your system from the internet.

I feel this was also rushed, because there is no MFA to secure the web app or the mobile app, that is also now cloud based. if someone has your login information, they can log in from anywhere and control your system.

​@Pools-3015 so this is why they can play my Sonos from anywhere via a Spotify app ?

if I change my login, would that cut off others that can access my Sonos?

Through Spotify is the key. Spotify ‘Connect’ requires you to ‘break’ the connection by playing another source on your Sonos. Once you’ve done that, you can go back to playing your local Spotify, but they won’t be able to reach your Sonos, as their Connect connection will have been broken. So any time you have someone over, and they access your system with Spotify Connect, just temporarily play another non-Spotify stream when they leave, and you’ll be the only one with access. 
 

Translation:

Gennem Spotify er nøglen. Spotify 'Connect' kræver, at du 'bryder' forbindelsen ved at afspille en anden kilde på din Sonos. Når du har gjort det, kan du gå tilbage til at spille din lokale Spotify, men de vil ikke være i stand til at nå din Sonos, da deres Connect-forbindelse er blevet brudt. Så hver gang du har nogen forbi, og de får adgang til dit system med Spotify Connect, skal du blot midlertidigt afspille en anden ikke-Spotify-stream, når de forlader, og du vil være den eneste med adgang.

Ingen kan få adgang til dine Sonos-produkter fra en fjernplacering uden dit brugernavn og adgangskode – det samme kan sikkert også siges om dit lokale netværk og/eller WiFi til hjemmet... så svaret er ikke at dele dine kontooplysninger.

Translation:

No one can access your Sonos products from a remote location without your username and password - same can probably be said for your local network and/or Home WiFi too.. so the answer is to not share your account credentials.