IBM and the Holocaust by Edwin Black describes the use of Hollerith/IBM punchcard technology by the Nazis.
That number tattooed on your wrist? Your Hollerith punchcard number.
One of the books conclusions is that, although the general Dutch population exhibited immense personal heroism in defence of Jews from home and abroad, the Netherlands had one of the highest rates of deportation to concentration camps because of its extremely thorough, up-to-date and accurate census and address records.
Whereas France had a much lower deportation rate because, although the French attitude was broadly "Hands off all Frenchmen, Jewish or otherwise, but we're not so bothered about all those bloody refugees," the French didn't have the same level of accurate, machine-readable records. And then actively frustrated Nazi attempts to create them - not recording religion, for example.
Once a database of any kind has been created, it can be used for all sorts of purposes. Legislation is a very weak, malleable control compared to not having the database. The more searchable and analysable the database, the more imaginative the uses you can come up with.
I'm not trying to wildly scaremonger, but it's a Thing That Can Happen.