Controlled Acquisition and Abstention in Three-Channel Score Conflicts

When audio, video, and text disagree, prediction accuracy alone does not reveal whether another source is worth acquiring or whether the system should withhold an answer. We separate these decisions in a controlled benchmark: a policy sees two signed scores, can request a third at a cost, and may abstain. The primary evaluation uses a mechanism-specific reward: abstention is correct only for one designated ambiguity mechanism and is scored as incorrect on mixed corruption. We call accuracy under this target targeted decision accuracy. Matched controls show that the threshold policy makes the same final decisions as an always-request policy while issuing fewer requests. Its advantage over always-answer fusion depends on rewarding abstention for one specified ambiguity pattern. Under the mechanism-conditioned target, the threshold policy reaches 0.789±0.006 targeted decision accuracy and 0.481±0.014 utility on the partially held-out synthetic split across 83 seeds. A zero-request majority reference that receives all three scores reaches 0.626±0.008 and 0.252±0.016; these results use different information budgets. A matched-budget test uses one terminal rule that allows the requested score to change the action. The train-only value selector improves utility over no-query and matched random at 10% and 25% budgets, but pair uncertainty has higher utility at every budget and the learned selector reduces utility at 50% and 63.7%. At those higher budgets, the learned selector has slightly higher non-ambiguous binary accuracy, so the utility result is not an unqualified accuracy ranking. Under the all-abstentions-error target, Threshold utility falls below majority, reversing their ordering. At the central temporal setting, full-trace controls match the neural models, while position perturbations separate them. On voice and face emotion clips from held-out actors, eight-frame fusion has opposite signed accuracy differences across two frozen encoder pairs; both actor intervals include zero. Matched-request routing gains are small and uncertain. Together, these results distinguish full-modality accuracy from pre-request selection value and show that the latter depends on the request budget and the observed-pair ranking.