The only appropriate visa to get paid is a work visa, like H1B, O1 or J1. He didn't have one, his J1 is expired. His situation is peculiar because as a scholar there is an exception. But if it had been to, say, tech talk at a conference, you can't get paid.

So I think it's relevant to the article because that's probably what the CBP agent was thinking. And the fact that he'd have been doing it for 30 years doesn't change anything.

Otherwise as French we don't need a visa just to visit the US, we are on the visa waiver program (ESTA).

> The only appropriate visa to get paid is a work visa, like H1B, O1 or J1.

No. There are plenty of situations where you can get paid in the USA without having a work visa. As you mentioned, the scholar in this article is one example. Another example: my spouse has a H-4, which is not a work visa, but has received employment authorization (EAD) and can get paid. Another example: athletes can enter the USA on a B-1, which is not a work visa, and get paid prize money.

We could keep going, but the point is that a rule with too many exceptions stops being useful and just becomes a false statement. This led the first CBP officer to incorrectly detain the scholar in the article. This also led the author of the original comment I replied to to visibly stop reading the article halfway through, and post to HN that the scholar did not have an appropriate visa and that it was the university's fault, both of which are explicitly debunked at the end of the article.