It has its own wifi network it broadcasts - an internal wifi router that makes its own network. There's no option to disable it. You can stop it from connecting to your devices, but you can't stop it from broadcasting. You don't know what information it's collecting as your devices constantly query what wifi networks are around them. Even if the tv has no internet connection it still broadcasts a wifi network.

I imagine the same way google improved their location services by driving around and literally collecting wifi network information, vizio can see where any TV not connected to the internet physically is if they send someone to drive around and look for their own TVs wifi networks.