Go to the part of the movie where Melody is getting dressed for the ball and Ariel is coming. When she is tying the ribbon that Sebastian gets caught in, her hair is down. The camera cuts to the door then cuts back to Melody putting a crown on. At this point her hair is in a ponytail. The camera cuts away to show Ariel coming into the room. You can barely see Melody’s hair, but you can tell that it’s in a ponytail. When the camera cut back to show just Melody, she bows and says, "I'm ready!”. Her hair is back down and her crown slides off her head. This is such an obvious slip-up, I can’t believe it wasn’t prevented.