An initial brainstorm: The verification mechanism could be implemented in the addition of any profile. If you find a duplicate profile that not is a MP, Geni would ask if the profiles are the same or if the profile to be added is another person (an homonymous). This is possible! If the profiles are the same person and the existing profile is an MP, then the addition would be denied and could offer an option of merge with some restrictions (to be think). If you are adding an ancestor as the son of a MP, so I'll need your experiences to think of a way of Geni decide what to do.
Ancestris, GenealogyJ, GenoPro, My Family Tree, Ancestral Quest, Family Historian, Family Tree Legends, Gramps, Legacy, RootsMagic, Visual Family Tree Maker... all this softwares have a "Tree Match" tool. The comparasion process of fields is very boring.