Dirty Dancing - Blonde Bomb
In the scene where the Housemans are driving up to the hotel, you plainly see the mom is blonde, however, when Lisa complains about the shoes, the mom has red hair then & throughout the movie. I know that the original actress that was to play the mom was blonde but she got sick and was replaced by Kelly Bishop and her red hair. Maybe they thought this would not be noticed or maybe they did it on purpose as a tribute to the original actress or maybe they just forgot to replace it. But for me, it was really obvious, blonde hair and different style.