&quot;Supposed to&quot; implies either a requirement or a moral obligation. There is neither. &quot;Should&quot; doesn&#x27;t have that same sense. Perhaps the word you meant? It would very much surprise me if that fine print exists as I looked for terms like that when I moved overseas, to make sure everything was legitimate.<p>Such a requirement is very unlikely for travelers. It&#x27;s just not practical given how often plans can change. (I visited a salt mine in Austria. To my surprise we crossed into Germany during the tour. Would I need to tell the US about those 20 minutes in Germany, and when?) How much would it cost to run such a system? What happens if the system breaks - and we know the foreign tourist tracking system breaks? What are the advantages to the US?<p>It&#x27;s more possible for permanent residency. But the US doesn&#x27;t even require that of domestic citizens, despite the clear advantages there would be to know where people live. So I don&#x27;t think it&#x27;s going to happen any time soon. And what would be the penalty of getting it wrong?