I think you are making it more complicated than it needs to be.
We already flag the problem taxa. We just hide the flags behind the scenes (or add to CV clean-up wiki). I’m just saying to make these flags more public.
This is not something which has ever crossed my mind on iRecord, where they have a version of this idea built-in to the system. Even if it did, I don’t see how that would be worse than it is at present, where a large portion of users don’t pay any hindrance to CV accuracy whatsoever.
If iRecord can do it, I don’t see why it would be technically insurmountable to have something similar on iNaturalist. And from a coding POV I don’t really get why this should be so complex tbh. The closest thing I can think of I’ve done was a software development class learning about model-view-controller and similar hierarchies - under those sort of standard frameworks at least, this would seem fairly straightforward to me - wouldn’t it just latch on to the existing structure ?
I think this would happen organically, as it’s crowd-sourced. But if there were extra care taken beyond that which is necessary for a period, it wouldn’t be the end of the world. Better to encourage the users to err on side of caution than the opposite, as we have at present on the whole.
I am not sure about other taxa, but when I’ve looked at the problem taxa on the CV clean-up wiki for Diptera, I don’t see much up for debate. These are known issues most identifiers would agree need help to mitigate. If a flag were misapplied, and people were warned unnecessarily until the flag was later revisited, I don’t think that would be the end of the world. Again, better to err on side of caution.
A generic warning flag just to say to take extra care on this taxa would just be a nudge also - it wouldn’t require policing so extremely imo. Going to the detail on the flag would enable the user to decide if its relevant to them.
Visually-speaking, I can’t imagine a much simpler solution to training users that CV suggestions aren’t always to be relied on. What simple solution to training users did you have in mind?