Corrected entry: At the banquet, Judy is wearing a black top and white pantsuit. The next morning, in the observation room, she is wearing a pink top and black slacks. Then, in the lobby, she is wearing the black top and white pantsuit again. However, between the scene in the observation room and scene in the lobby, we see Mr. Smith check his case and find that he has Judy's clothes, so she couldn't have changed.
Corrected entry: When Judy and Howard steal the wedding couple's car, Judy gets in the driver's seat. A few minutes later, Howard is shown driving just before they drive off the pier into the water.
Correction: You can see Judy and Howard start to trade places after Judy says it's her first time driving. You never actually see them change places, but they begin to change before the shot changes.
Correction: In many of the scenes shot in her hotel room, we see multiple cases. Her change of clothes could have been in any one of them. Smith has just one of her suitcases.