[eximius]

Legally speaking, are they on the hook if they merely say that and don't take preventative measures against US citizens? It could come back to haunt them if they ever want to expand to the US down the road and didn't take precautions.

[londons_explore]

A simple dropdown saying "citizenship" and then turning red with an error message saying "United States is not allowed. Did you mean United Kingdom instead?" will encourage most people to put something else.

Then the company can fairly legitimately say "The customer lied to us about their citizenship. We took all reasonable measures to determine their citizenship, because there isn't a freely available database of which people have which citizenships"

[tfha]

My understanding is that the SEC expects you to require proof of an alternate citizenship via a passport. Simply having a drop-down that users can lie about by clicking a box or using a VPN is not good enough.

[AlexCoventry]

Yes, they are on the hook in that case. (Not lawyer, not legal advice.)