The rule I omitted from the quote was "hospital affiliation". In the paper, they try a variety of combinations of rules, including some where failing any one ru

The rule I omitted from the quote was "hospital affiliation". In the paper, they try a variety of combinations of rules, including some where failing any one rule classifies the paper as fake. The meat of my complaint remains even when they're intersecting with other rules. We should not be incentivizing people to use emails that predictably go dead in O(years). It is quite a common annoyance to read a paper, want to contact the author, and not be able to because the email they listed is dead, requiring searching for where they currently work and trying to find their email at that new place, with mixed results. Yes, a private email is predictive of a paper being fake, in the literal sense that P(fake|privateemail) > P(fake|institutionemail). I get weird looks at work for using my permanent email address because of it. And probably if we select on that as a way to discard papers, it will initially appear to work and then start to look like it's working even better because anyone trying to give permanent contact info will be forced to switch to be published/cited/taken-seriously. But that's a bad outcome. Also, if you systematize this rule, paper mills will just start using emails that appear institutional, because this is a simple rule to defeat.