Other mistake: When the clock strikes 8 o clock, the 11 (XI) on the clock reads 12 (XII) in roman numerals. This is just in-between the scene with the mice making Cinderella's ball dress and the scene where the carriage arrives at the home to pick the stepmother and stepsisters up for the ball. (00:36:50)
Other mistake: At the beginning of the movie, where Cindy opens the drapes outside of her stepsisters' bedrooms, you can see a slight stutter in her walk just as she reaches for the drapes. Looks like a camera mistake - the cels were out of sequence there.
Other mistake: In the scene where Gus and Jaq are trying to get the blue beads from Lucifer, Gus runs into the wall with the beads and the strand breaks, even frame by frame you can't see a string holding the beads together.
Answer: Cinderella's entire outfit was magically created by the Fairy Godmother. Not only was the spare shoe Cinderella had in her possession identical to the other one, it likely would be charmed so that she is the only one who can wear it. It's similar to young Arthur being the only person who could pull Excalibur from the stone because he was the true king. No other woman who attended the ball wore glass slippers. If they had, they'd be able to also produce the spare shoe as proof.
raywest ★