On COPE Commitments and Double Dripping

In "How much does a COPE-compliant open-access fund cost?", Stuart Shieber, the architect of Harvard's historic faculty consensus on mandating Green Open Access Self-Archiving, has explained that the purpose of the "Compact for Open Access Publishing Equity" (COPE) commitment of funds to pay Gold OA publishing costs is (1) to provide a "safety net" for publishers, that (2) COPE does not fund hybrid Gold or (3) double-dipping, and that (4) the amount of money involved is trivial. My own objections to COPE are not based on double-dipping, nor on the amount committed; they are not even based on COPE per se. They are based on committing to COPE without first committing to mandating Green OA.