The Entity Resolution problem has been widely addressed in the literature. In its simplest version, the problem takes as input a knowledge base composed of records describing real world entities and outputs the sets of records judged to correspond to the same real world entity. More elaborated versions take into account links amongst records representing relationships between the entities which represent. However, none of the approaches in the literature question the validity of certain links between records. In this paper we highlight this new aspect of "link validity" in knowledge bases and show how Entity Resolution approaches should take this aspect into consideration.