The details are unclear anyway. What about Schengen citizens living in the UK? I can imagine they'll generally let people in from UK and Ireland but question them about travel history and maybe proof of residence. Lying to a border agent gets you banned for life, that should be a decent deterrent.

In the end, it's not like a terrorism threat where the ones trying hardest are the ones you need to catch. Here, keeping 99% out can suffice easily, esp if the others are also questioned and are getting temperature checks.

You realize that the U.S. has probably many more infectious areas than Europe?

They certainly do have many but travelers from Europe could still introduce more infection clusters, especially in major cities.

I don't think the people who made this decision are on Hacker News.

> Passports for EU citizens aren't stamped anywhere in the EU. I live in Denmark. Would the USA know if I flew to the UK, then the USA?

This kind of question is a weird one to me. It's like "oh, marijuana prohibition hasn't worked so we should tax it and regulated it".

If you're breaking the law, there's sanctions. You may or may not get caught, and you may or may not be penalised, but that imperfection doesn't decide if it's valid or not. The jails in every country have murderers in them, but murder has been illegal since time immemorial. No-one proposes that we allow murder because with the prohibition we simply wind up with people in prison.

And there's a big difference between free movement of people versus a limited funnel of people. If it's still early enough, that could make the difference between something that is containable and something that is not, and it might make the difference between ICUs that can cope with the peak and being completely overwhelmed. (However, I think the horse has already bolted on this one.)

it's a legit question which is the pillar of (software) security thinking. It's called parallel or adversarial thinking https://en.wikipedia.org/wiki/Parallel_thinking

what would work in that case is take the Channel Tunnel to England, then lie about how long you've stayed in the UK. It probably wouldn't work if you have taken a flight out/in the EU in the past months as that would show up to any customs official.

We saw many people in Italy fled south by train and car in the hours before quarantine was to be imposed in parts of the north.

I wouldn't be surprised if some people in Europe are making similar "escape plans" via the UK, if they feel they need to be in the USA for some reason.

As an example: a parent of an international student, whose university in the USA has just been shut down.

> Would the USA know if I flew to the UK, then the USA?

I would imagine they will have you fill in a recent travel form. And make it clear that you'll be in a lot of trouble if you don't answer truthfully.

I suspect it is trivial for the US to check who boarded flights across the world, and you left many other digital footprints (payments, cell phone activation, etc). IANAL but I believe that lying to immigration when entering the US is a pretty efficient way to get banned from entering for life.

Since UK isn't in Shengen don't you need to show ID on entry? Surely they record who comes in

All EU citizens (including Irish) and British citizens show a passport or national identity card when entering Britain or Ireland, or when entering the Schengen area.

The document is checked, but it is not stamped. GB/IE←→Schengen checks used to be very simple — often just a glance, no checking the chip or swiping the passport in a reader. Often it was just one or two customs people standing by the gate and looking at each document, not even with a desk. Now (since the refugee thing?) they do swipe the document on the passport-reader-machine.

I assume an electronic record is kept (at least for some period of time), and it is surely shared within the EU+GB, but I don't know if it would be shared to the USA.

(If the situation were reversed, would the USA tell the EU about American citizens who've crossed the US/Canada border using their driving license?)