In many application scenarios, such as cloud computing and network function virtualisation, entities from different domains or their interactions are short-lived. Yet, it is often necessary to ensure accountability of events recorded by such entities about their application-specific interactions. The distributed and multi-domain nature of this problem makes a decentralised architecture imperative, particularly in the context of key management and trust. This architecture also needs to address challenges in terms of cross-domain privacy and confidentiality of shared data. For concreteness and without loss of generality, we consider the use case of firewalls as virtual network functions (VNFs) across multiple domains where short-lived firewall VNF instances spin up and down, logging events (e.g., security incidents) during their life spans. Such event logs need to exist, for purposes of accountability, beyond the life-cycles of their generating entities. In this position paper, we present a dual blockchain framework that facilitates the verification of integrity as well as authenticity of events while supporting privacy and confidentiality of data shared across multiple domains.