Comment by scott_w

> When the Nazis took over the Netherlands, they relied on the state's exceptional record keeping of individuals to hunt down the undesirables. Many people died that didn't have to die because the bad guys were enabled by the data systems built by the good guys.

In many cases, they looked at the census records; something that most western nations have today anyway.

Let's be real: if your government decides to slaughter an entire class of people in its own borders, there's nothing you as a citizen can do except flee and hope to get out without being caught (or sent back).