I already logged a version of this as a feature request but it was declined by moderators unfortunately ( before I started this thread ).
I will try and return to this thread later to comment in full on your points @pisum.
But one thing I would say for now is that I don’t believe this is a niche issue.
I guess if you weight all observations equally perhaps so, as this is doubtless a very limited problem in birds for example where we have ample expertise. But in inverts trapped at higher levels it’s certainly an issue.
For a visible example of impact, look at Opiliones observations trapped at order in Europe. We have two active experts, but not three, so the issue with the algorithm is quite well displayed in this particular instance. Basically any obs which have 6 IDs are affected here - which is 14 out of 30 observations on page 1 :
