Actually it is not. Luke-jr's proposals are actually the ones that fullfil that aspect of the agreement. Firstly, the group "core devs" did not agree to anything, nor were they represented at that meeting. Rather a couple people who frequently contribute to Core (including luke-jr) were there and those people agreed to propose a hard for proposal which they could recommend. But that does not mean that that proposal would be implemented or accepted by the rest of the Core devs. Luke-jr fulfilled that part of the agreement; he made a hard fork proposal which he could recommend to Core, but the rest of the Core devs did not really like it, so it was dropped.

IIRC Sergio has never contributed to Core not was he at the Hong Kong meeting.