I had a fairly lengthy look in to this because my contract doesn't have overseas tethering. Tried a number of easy and complicated solutions that were suggested online, none worked.
There is a workaround I used to use, not sure if it will still work though-
On the device you are connected to change the browser to spoof a phone or tablet (think I used to do it in Firefox), and it could bypass the network picking up on it.
I had a fairly lengthy look in to this because my contract doesn't have overseas tethering. Tried a number of easy and complicated solutions that were suggested online, none worked.