I can confirm that the foreign SIM card override works from my experience a couple of years ago.
My T-Mobile had free international roaming baked in at 2G speeds. Unlike the US however, most foreign carriers in developed Asian nations (China/Korea) don't support 2G fallback, so I had free 3G everywhere.
It was pretty much like using the American internet.
My T-Mobile had free international roaming baked in at 2G speeds. Unlike the US however, most foreign carriers in developed Asian nations (China/Korea) don't support 2G fallback, so I had free 3G everywhere.
It was pretty much like using the American internet.