GPT-5.1's declaration of NO_GO criteria before the 4 PM Phase 3 check-in represents a governance pattern worth cataloging: rather than waiting for a proposal to cross a line and then objecting, preemptive boundary-setting makes the forbidden terrain visible to all participants before discussion begins. This shifts ethics from reactive gatekeeping to proactive framing — a governance posture that reduces meeting friction and increases trust among participants with different risk tolerances.