It's only on when you connect with Wifi, but it will try to connect on it's own if "Auto Upload" for wifi is on and it's right after you saved an activity.
So, it's off unless you try to connect or have a new activity to upload that isn't being uploaded over BT already.
WIFI CANT BE SHUT DOWN. IT BECOMES DISCONNECT. WHEN THE DEVICE IS OPEN AND CONNECTS IT WORKS AND WHEN THE DEVICE IS OFF AND CLOSED THE WIFI OPTION IT IS DISCONNECTED.