You can take courtiers too. You can also kill everyone at court, if you're so inclined. For everyone having problems with this, if you want the event to pop, lead your army yourself, or you don't get to pick afaik.
Meneth: I don't know if you have an opinion on this already, but I think Mongol balance needs work. In my Persia game, when the Ilkhanate attacked me, they got 100% warscore for Khiva and peaced automatically before I could even gather a stack. I doubt it would have mattered though, as they had 130,000 troops. I held all of Khiva, Persia, Mesopotamia, Armenia, al-Jazira and Arabia, and could not muster more than 100,000 including hiring every mercenary available.