I wonder if this is more about trying to make Google sign up for...
Coordinated Vulnerability Disclosure
"Under no circumstances will Microsoft release details of an unpatched vulnerability unless evidence of public attacks exists, as outlined in subsection F, Exceptions to the Vulnerability Public Disclosure Process, below."
So as long as MS responds they don't need to release a patch unless the exploit surfaces or the details are known.
MS: sign this
Goo: err no
MS: well we won't release our patch until Tuesday
Goo. o O (hmmm if we break our own deadline it will just give them more ammo to press us to sign it)
Goo: releases details as stated in their terms and conditions.