The NYT on the detained tourists I've been writing about: https://www.nytimes.com/2025/03/13/world/europe/german-tourists-detained-deported.html.  Better late than never.  The German woman is now back in Germany, but the Welsh tourist is still in detention, AFAIK.  I called the UK Embassy in San Francisco, but they are unable to give out information on British nationals due to privacy constraints.  I called the ICE number for verification of detention, but the voicemail system I was directed to was full and not accepting more messages.

As I noted earlier: if you don't have a US passport, you should not travel to the US at present.  Detention is cruel and unpleasant, and for an indeterminate length of time.  This warning should be posted as a travel advisory on other countries' government web sites.