It is typical that when assessing a Site, that a Primary Contact is the interface (Station Manager, Lease holder, etc) Presently the Lookup field type can search for Mandatory Fields which enables First or Last Name, but if searching for a person, it would be good to see the Full Name and supporting attributes (Mobile and Email) otherwise which "John" or "John Smith" is being attributed in the Inspection Responses.

Filtering helps (based on contact type), but does not remove the possibility of duplication.