[peyton]

You're completely right. There are serious downsides.

However, I think this question (and a lot of the crappy things about the US) exist to deal with and automate problems at scale. Scaling is hard. Scaling solutions are overkill if you don't have a scaling problem.

In this case, the problem is strong due process protections and allocating court resources. You might not hold a person without involving the courts if you suspect them of terrorist ties, but you can if they lie on a form or tell you they're a terrorist.

I don't know the specifics, but one could imagine a concession of due process if, say, the person held for their answer on the entry card is guaranteed to appear before a judge within three days.

Automate the process and you get silly situations like the one above. Don't automate the process and somebody eventually screws up and denies due process or lets a suspected terrorist through without scrutiny.

And again, yeah, the entry questions could be handled better, but it's a serious juggling act scaling it up and fitting it into our legal framework.