For the record, let me state my position, and I think this is also roughly the position of Canonical and the Ubuntu Community Council though I haven’t caucused with the CC on this specifically.

We have declined to discuss any agreement with Microsoft under the threat of unspecified patent infringements.

Allegations of “infringement of unspecified patents” carry no weight whatsoever. We don’t think they have any legal merit, and they are no incentive for us to work with Microsoft on any of the wonderful things we could do together. A promise by Microsoft not to sue for infringement of unspecified patents has no value at all and is not worth paying for. It does not protect users from the real risk of a patent suit from a pure-IP-holder (Microsoft itself is regularly found to violate such patents and regularly settles such suits). People who pay protection money for that promise are likely living in a false sense of security.