Over on birdsite, Amal El-Mohtar, an sf poet and author, has recounted a truly awful (yet typical) experience she had with US immigration authorities.
https://twitter.com/tithenai/status/936224584017121280
She's Arab Canadian.
The sf community holds regular international cons, often in the USA, and there is a standard questionnaire that is asked of each one. I've just proposed adding the following questions to it (first draft, but the session is tomorrow, so I just sent it).