Tethering does NOT WORK while roaming IME Thailand, Malaysia, etc. Even thought sometimes you can turn it on on the phone, it doesn't work.

Tmo has some plans with the ability to roam (simple choice) if using a tablet with a sim, BUT if you don't have a plan that allows it I was told a few days ago that IT TAKES 5 WEEKS for it to go into effect, so my thought of adding a higher level to my sim tablet (and taking it instead of my preferred one with only wifi) for a trip next week is a no go.

So much for no contract instant change of service!