Promise not to settle on ~The Planet~

[TheMeInTeam]

It's also a hidden rule, which is an objectively poor design choice in a strategy game. Hidden rules are something worth disrespect, not something defensible.

There was kind-of a case to be made when it was purely an algorithm for "how the AI reacts", but now that there is tangible game-defined currency involved (grievances, possibly emergency) hiding the rules for this is strictly poor implementation, and tiresome since it's far from the first instance of such in recent Civ titles.