Semantic Web technology is based on the Open World Assumption (OWA) where absence of entities being searched does not entail negative response rather simply treated as facts "not available at the moment."??On the one hand that indicates anticipation of future enhancements of the fact store while in other cases it is not preferred in situations where an authoritative answer is needed. Closed World Assumption (CWA) on the other hand returns definitive yes/no answers even in situations where future enhancements are inevitable. We wish to distinguish among the situations where one or the other assumption would be advantageous to use. Such distinction could cater for faster services discovery and more wholesome services orchestration. We apply this approach to discovering semantic Web services being offered by autonomous semantic robots out in the field and for building the unified worldview common to all. Consequently, the OWA-based paradigm alone is not suitable for most robotics platforms where cardinality and negation is not sound as well as in CWA. Therefore, we argue and display that a strategy to draw and utilize benefits of both world assumptions is beneficial.