To add another example scenario to your list that I have come across multiple times: An observer comes across a plant in a seemingly un-cultivated area that they insist was wild/feral. The plant appears almost certainly to be a specific ornamental hybrid that I know is always sterile, and does not seem to readily propagate/invade vegetatively outside of careful cultivation.
I am sure they are reporting what they perceived in good faith, but that doesn’t mean I have to believe they are right. Maybe it isn’t completely impossible they could somehow be correct. However, balancing their credibility with knowledge I have it seems a far more likely possibility is that someone has just planted or discarded it in an incredibly weird place for some unknown reason (perhaps a misguided beautification attempt).
This is a good point, however my own situation isn’t one of these scenarios. At least, I don’t think it is. The species I encountered can reproduce by seed and in fact this is not the only time I’ve encountered it in a wild setting.
The observer did not tell me some reason it could be impossible. They merely told me what I have already posted in my OP. The user failed to provide me any evidence to believe that this plant was cultivated.
Right, and in this context in situ pictures wouldn’t make a difference anyway; I don’t have any reason to doubt that the plant was there, just that it could have gotten there of its own accord.
Because this topic is now solved, and has devolved to the point of discussing a specific issue on a specific observation with specific users (with all but usernames being included), I think it’s best to close the thread, as it has veered into the territory of calling out specific users over actions on iNaturalist itself.