The fact that CM does not inform the parent visibility scope is not nice, but I doubt if it should prevent you from selecting some other publications. Keep in mind that a single group might be used in several parent groups with different visibility scopes. More to that, effective visibility scope is determined not only by the immediate parent group but also by all parents if there is a complex hierarchy of nested groups.
The practical approach might be to highlight the current set of effectively visible groups in the UI, but do not prevent from selecting other publications if needed.
In any case, let's keep this idea in the under community review state to collect more votes and comments.