Deliberate mistake: Throughout the movie, you can see the size of true-size Rosemary, particularly her waist and legs. Notice the size of undies she was going to purchase when she and Hal first meet. Notice the size of her bathing suit bottom. However, in the scene where she throws her purple nightie undies at Hal and he catches them: the panties are WAY TOO BIG. Especially the leg holes, which could go around her true-size waist.