When Silence Misleads: Censored Observation-aware Verification for Collaborative Perception

Object-level collaborative perception lets an ego agent recover objects it cannot see, yet every fusion rule in use reads the ego’s own silence as evidence: a remote proposal the ego did not also detect is discounted. We show that this silence is censored by observability. Among uncorroborated remote proposals, the fraction that correspond to real objects falls from 10.7% to 2.0% on real data and from 6.0% to 0.1% in simulation as the ego’s opportunity to verify the claim rises, while the confidence the sender reports is flat across the same axis — so a rule that reads scores alone cannot separate an unobservable hypothesis from a refuted one. The same structure defeats calibration: scores well calibrated on ego-visible objects are over-confident on ego-invisible ones, and neither message-observable context nor corroboration counting repairs it. We formulate missing corroboration as a censored observation: an absence is evidence only where the ego was eligible to observe. COVE is the minimal operator enforcing that admissibility condition — a remote hypothesis is attenuated only when the ego was physically eligible to verify it and did not. It needs no retraining or extra message payload. On six frozen scene-level holdouts spanning real and simulated data and a heterogeneous LiDAR/camera pairing, it improves aggregate AP70 over the score-mean late-fusion rule it is applied to on every holdout (+1.9 to +5.7 pp, every interval excluding zero) and ego-invisible AP70 by up to +20.8 pp, significantly on the four simulated holdouts; treating silence as a negative vote costs up to −29.1 pp, and uniform down-weighting buys aggregate accuracy at the cost of the ego-invisible subset. A controlled intervention — identical proposals, association and emitted geometry, with only the score aggregation replaced by evidential aggregation— improves aggregate AP70 in all twelve bootstrapped comparisons with every paired interval excluding zero, so the effect is not a property of one scoring rule. Across six more expressive extensions, none yields a consistent held-out improvement over the minimal operator.