Jeopardy! and the Attack of the Guest Hosts

  I know the show is taped weeks or even months in advance. Does that mean that the "just announced" guests hosts have already taped shows, or are they planning to? If they haven't taped yet, is there still a possibility of a viewer protest? Anything to keep "Dr." Oz from appearing on the show. He's just one step up from the MyPillow guy (I hope he's not on the list).