Presence Without a Token After Optical Smoke and a Dark Plant

Two questions remain after the three Plane C records of 10 September 2026 (10.5281/zenodo.22685824, 10.5281/zenodo.22687883, and 10.5281/zenodo.22689142). What does a nano uncrewed aerial vehicle (UAV) owe a neighbor it can only hear? How does an airframe that never received a task token still bind or refuse work? Both questions occupy the same remaining interval: after a heartbeat and before a framed field. Neighbor-first Plane C is keep-alive, relative pose, task token, and abort. After optical smoke and a dark plant, ultra-wideband (UWB) or 60 GHz still carries pose and the token field, and lead-free potassium sodium niobate, K0.5Na0.5NbO3, written here as KNN, still carries a heartbeat or an abort trigger. Hearing a neighbor on that acoustic host is presence. It is not a token transfer and it is not relative pose. An airframe that never received a token holds an empty cache. Empty cache is refusal of assigned work: no task identifier is binding, and heartbeat does not write one. Work binds only when a framed token arrives on the pose host. Abort still freezes actuation if the heard class is abort. This is a design paper. It reports no measured fleet.