Right, that&#x27;s often how they do it, but you seemed to be saying that this was something that <i>should</i> always be done. Maybe I misunderstood.<p>As for how countries actually do it, there are a lot of borders out there where you can legally cross without telling anybody, like the borders in the Schengen area (possibly excluding France at the moment, not sure what&#x27;s going on with that) or the border between the UK and Ireland. Certainly, tracking is the norm, but it&#x27;s not universal.