Are you referring to annotations or observation fields?
The first part of your question sounds like it is about annotations (it is not possible to disagree with values entered in observation fields); the second part sounds like it is about observation fields (there are a limited number of annotations that should be clearly distinct).
You do not get notifications if people disagree with an annotation. It is not possible for anyone except the annotator or observer to correct annotations, so some people may @ mention you if you have entered an incorrect value. It is often important to @ mention the annotator rather than just commenting on the observation, since in many cases the annotator may not have interacted with the observation otherwise and thus will not be subscribed to get notifications for it.
I believe you should get notifications if someone changes the value of an observation field you have added.