Service choreographies are technical contracts which specify the message-based interactions among collaborating parties, called participants. The interaction paradigm for modeling choreographies foresees the specification of the messaging occurring among the participants from a global perspective, e.g. as a workflow in which the message exchanges among the participants are modeled as activities. Since the ordering and timing of the message exchanges are specified from a global perspective, it is surprisingly simple to specify choreographies that cannot be correctly enacted by their participants. A choreography that is specified so that its participants cannot play their roles is said to be unrealizable. Realizability is a fundamental property of interaction choreographies. In a sense, an unrealizable interaction choreography fails its purpose: it specifies a distributed messaging behavior that cannot be enacted accurately by its participants. In this work we present a method for the analysis of the realizability of interaction choreographies based on the concept of participant awareness. Participant awareness is a symbolic representation of what a participant ``knows'' of the global state of the enactments it partakes. The realizability analysis presented in this work is specified on the basis of ChorTex, a choreography modeling language based on process algebras. ChorTex has exception throwing and handling constructs that are very similar to those available in orchestration languages like BPEL, and that can be used to realize interrupting, event-based constructs like termination end events in BPMN v2.0. Our finding is that, due to the distributed nature of choreography enactments, modelers must use such constructs with extreme care.