I think Morgan and Morgan's concern is likely to be Disney's history of litigiousness. Why wait til after the ad airs to get a judgment?

We don't have to conjecture about that, the linked article clearly states "The firm said it had filed the lawsuit based on Disney's 'history of aggressive enforcement of intellectual property rights,' including a trademark lawsuit the media giant filed against another company on July 16 over jewelry depicting 'Steamboat Willie' characters"