Spotify Connect even in Offline Mode and outside WLAN ?

[Zoriel]

Hi, friday i sat in the office listening to music through spotify on my mobile phone. Spotify was in Offline Mode and WLAN was turned off when suddenly the music switched and i noticed that my wife at home started the desktop app playing music.

Spotify Connect popped up on my mobile phone asking where to play the music.

Is this supposed to be possible ?

Thanks

Oliver