Hmmm... my 830 was set to allow the USB connection without asking and the info on the MS page didn't mention being able to turn it off just that:
"And when your phone's connected to your computer using a USB cable and your computer is connected to a network, your phone will choose your computer's network connection over the other connections. "
That to me says that I am not just transferring files and stuff from phone to pc but also using the internet connection of the pc for hitting the internet.
Anyhow, I've got it now set to ask about allowing usb connections and will be damn sure to never plug into my computer at work again just to be safe.
:
"Your phone will typically choose a Wi-Fi connection over a cellular data connection when they're both available. And when your phone's connected to your computer using a USB cable and your computer is connected to a network, your phone will choose your computer's network connection over the other connections. "
Thanks Daniel.
What that setting does it .... in simple words
you can use your PC either as a charger or you can use it to transfer files.
Why the option is given ?? Turning off the storage access enables faster charging through a PC USB port.
It has nothing to do with your data(internet) .