Institutional agreements with publishers on proxy deposit into institutional repositories are an extremely bad idea, for a number of reasons:
1. The only sure way to achieve 100% open access is to have a rational, systematically verifiable system of deposit and monitoring.
2. Instititions are the providers of all research output, whether published in OA journals or subscription journals.
3. Spontaneous, unmandated OA self-archiving by authors is growing much too slowly.
4. The only way to accelerate OA to 100% is for authors’ institiutions and funders to mandate OA self-archiving.
5. Institutions are the only ones in a position to systematically monitor and ensure OA mandate compliance, such that all of their research output is self-archived in their institutional repository.
6. If some deposits are institutional and some are institution-external (central), and some deposits are done by authors and some by publishers, it makes it impossible or extremely complicated to systematically monitor and ensure that all research output is deposited.
7. Self-archiving in the institutional repository immediately upon publication hence has to be made a mandatory part of the standard research work-flow for all institutional researchers (just a few extra keystrokes per paper upon acceptance for publication). (Even librarian proxy deposit is not a good idea.)
8. Instead allowing or encouraging publishers to do the deposit — either paid OA publishers, or subscription publishers after their self-imposed embargoes have elapsed — takes the control of OA provision out of the hands of authors and institutions, and leaves it in the hands of publishers.
Hence it is a far more effective and far-sighted strategy for institutions to adopt effective, systematic, verifiable institutional OA self-archiving mandates (reinforced by funder mandates) than to be drawn into any side-deals with publishers, whether OA publishers or subscription publishers. (To do so is a Trojan Horse or a Faustian Bargain — take your pick of metaphors!.)