I just came across this discussion, so my apologies for being late to the party.
Firstly, I was a little surprised to learn that atlases have this auto-expansion capability, because my understanding from reading the write-up was that they are supposed to provide a control for out-of-range observations. The bar for RG is not especially high (2 IDs) and that has a lot of benefits, but it seems troubling that spurious observations that get a confirming ID would automatically expand the atlas for that taxon. It seems a significant bug for that expansion to “stick” even if the ID is later corrected.
I see that several people have suggested adding an auto-contract capability to address the bug I just mentioned. But this can’t be as simple as just removing locations that don’t have RG observations, because that negates one benefit of manually creating atlases which is that we can define a set of documented locations even if there aren’t yet RG iNat observations for some of them. It seems that iNat would need to track which locations were auto-added and only auto-contract those ones.
On the topic of what level of detail is appropriate for auto-expansion, I feel this is a continuum and this may differ greatly among different taxa. I have been adding atlases for some monocot plants in California. Many mistaken RG IDs are for similar species in California counties beyond the documented range of the species being selected. I definitely want to know when people are finding these species in new Level 2 locations, but I’m not sure that always auto-expanding the atlas boundary is the right response. In contrast, if these species show up in Maryland or the Netherlands, it’s more likely someone will flag them as cultivated before they reach RG.
I wonder if there could be a per-atlas setting that governed auto-expansion behavior, so that curators could tweak how community IDs interact with curated content. For some sparsely distributed taxon, it might be fine for iNat to auto-expand at Level 1 or even Level 0. For an island endemic, even Level 2 auto-expansion seems like a net negative.