I think a choice in weighting could help these people too.
I wouldn’t stray outside my chosen taxa either for this reason, and I am extra wary if identifying outside my geography. If I could choose weight though, I would feel a lot more free to pitch in elsewhere and learn as I go. It would certainly feel more like a “field notebook”. Potentially messier, but more free-ing.
I could imagine various ways to implement it.
Possibly the simplest would be visual …instead of just “agree”, two choices like… :-
and 
With tooltips to explain difference.
Or a scale with some greyed out so you can toggle level of confidence : 
Alternatively, a button to “confirm” could be less visible than button to “accept” - like withdraw and delete are at the moment.