How long until foreigners are required to leave a DNA sample at US immigration checkpoints at airports when entering the US? Fingerprints have already been collected there for a long time.

Or just bring back the TSA air puffer machines (rev. 2), and say you're doing it to keep people safe from known terrorists with fake ID whose DNA you have on file. You'd have a full-population genetic database in no time, matched to identifying information, passport/license numbers, and travel history.

That incurs a lot of R&D costs and costs of installation, and people might not be okay with such a thing happening because it affects everyone. On the other hand, querying a DNA database doesn’t face much resistance because it only affects a small number of people.

That's a fun (and scary) thought. Thankfully we're not there yet. When we do get there I hope we'll have the same privacy concerns as we do today for these online databases.

It doesn't invalidate the current concerns, though.

How would it link to you? The DNA is useless by itself.