Revealing mistake: In the close-ups of the elves during the Coronation Ball, you can see the fishing wire used to attach their wings to their backs.
Revealing mistake: In the close-ups of the Queen as she dies, you can see the line of her wig on her forehead.
Answer: Because if Wendell and the switched dog somehow came in contact with each other then they would switch back. She does not want to risk this happening.
Scrappy