Some Genesaunts serve as Observers. Human Observers monitor events on Earth, but they must follow the Rules of Observation. The Rules of Observation are a simplified version of the Rules of Intervention.
The Rules of Observation require that those who are being observed do not become aware of the existence of Genesaunts. Human Observers who work on Earth are genetically similar to Earthlings.
Observer Base. Most human Observers live on the Moon at Observer Base and only a few Observers are on Earth at any time.
The Overseers make sure that Observers follow the Rules of Observation. If any Earthlings become aware of Observers then the Overseers either erase their memories or remove the Earthlings to Observer Base.
Most Observations of Earth are actually carried out by automated nanite probes. The main reason for having some human Observers on Earth is to create opportunities for some Earthlings to become aware that Earth is being Observed. When they do, they become Genesaunts and provide a means of making sure the other Genesaunts do not become too detached and uninterested in Earth. Also, Observers often become involved with Interventionists, those Genesaunts who actively violate the Rules of Intervention and try to alter the course of events on Earth.