I used to think that staying connected while traveling was mostly about data. Maps loading quickly, messages going through, directions appearing when I needed them. As long as the internet worked, everything else felt optional. Vietnam quietly challenged that assumption. It happened on my first evening, shortly after arriving. I had stepped out to find something to eat nearby. Nothing complicated — just a short walk, a few turns, and then that familiar pause when a place doesn’t quite match the directions you saved earlier. I sent a message. No reply. Then my phone rang. The call was brief. A...