Here's an excerpt:
The Wellcome Trust has not only showed themselves willing to fund OA, they also demand something in return for their funding. Authors are not allowed to use articles that should have been OA, but aren't, in their list of publication when applying for new grants. If the Trust find papers in reports, that do not comply with the OA policy, funding will be withheld. Non-compliant papers will also result in funding renewals or new grants being held back. . . .
The National Institutes of Health (NIH) has announced chances to their procedures regarding OA compliance. If non-compliant papers are found in project reports, further payments will be withheld pending evidence of compliance or a satisfactory explanation. . . .
The European Union is rewriting their OA policy for Horizon 2010. In Framework Program 7 (FP7), a Special Clause 39, demanding Open Access, was attached to about 20 per cent of funds. In Horizon 2020 all funds will have an OA obligation attached. And while the OA obligation in FP7 had a "best effort" clause in it (enabling you to be let off the hook, if you could document that you had asked for, but been denied, permission to self-archive), Horizon 2020 leaves no escape. If you don't comply, you have not fulfilled your contract. This will lead to funds being withheld.