Theoretically, you're right, but that would be a PR nightmare. If he were to ref another game, can you imagine the dynamic between him and Calipari? I would imagine that he will recuse himself from doing any more UK games to avoid any drama.100%
The NCAA will make sure to send a message that their referee assignments can not be dictated by intimidation or harrassment.
It would be a horrible precedent if the NCAA pulled Higgins from uk games.... and they know this.
He will referee a Kentucky game next year. Book it.