Such technologies always have an error rate, and these error rates are taken into account, by and large. There is a huge potential to harass people using such

Such technologies always have an error rate, and these error rates are taken into account, by and large. There is a huge potential to harass people using such technologies, particular such people whose complaints are most easily ignored. But that is more of a problem of holding the government accountable for such behavior in general, rather than trying to stop them doing their arguably necessary job in this particular instance. I'm generally against regulation or restriction of migration, by the way. But I'm also in favor of the authorities having a general idea who's coming and leaving.