Boundary Conditions (BCs) express situations under which requirements specifications conflict. They are used within a broader conflict management process to produce less idealized specifications. Several approaches have been proposed to identify BCs automatically. Some introduce a prioritization criteria to reduce the number of BCs presented to an engineer. However, identifying the few, relevant boundary conditions remains an open challenge. In this paper, we argue that one of the problems of the state of the art is with the definition of BC itself – it is too weak. We propose a stronger definition for the few, relevant BCs, which we refer to as Unavoidable Boundary Conditions (UBCs), which utilizes the notion of realizability in reactive synthesis. We show experimentally that UBCs non-trivially reduce the number of conditions produced by existing BC identification techniques. We also relate UBCs to existing concepts in reactive synthesis used to provide feedback for unrealizable specifications (including counter-strategies and unrealizable cores). We then show that UBCs provide a targeted form of feedback for repairing unrealizable specifications.