something the RFC standard recommend but doesn't require
but it being required is a de-facto industry standard for sending automated mails
and is clearly documented by support sides of large mail providers (like Google)
the mail standards only defines what parts you can put together, but widely fail to define how this parts can be interpreted, what are sensible combinations, etc.
and they don't cover spam/suspicious mail detection at all
so you can't just go by RFC, you need to read up on what all larger mail providers have as additional requirements (which mostly are the same, and Message-Id being the most common dominator) and then hope that another provider you didn't read up one doesn't have some other surprising rule (which doesn't tent to be the case if you don't do anything surprising, but it sucks anyway).
I don't think it is and I think it is a good idea. Not every company needs this, and often, ensuring backwards compatibility is preferable. But I can see a lot of very good engineering behind this.
I could be wrong (and probably am) but I think the black bar stays up for 24 hours.
So it is not surprising if the article moved to the second page when the person does not have instant name recognition.
Like a lot of things on HN, despite being enough effort that someone might complain, going to the second page is not a terrible inconvenience for the minimally curious.
They even have a Whistleblowing link at the bottom of their website: https://www.bankingsupervision.europa.eu/about/esfs/html/ind...