The Suite Life Goes Hollywood (2) - S2-E37
Revealing mistake: When Maddie and London are pulled off the cart by the horse, you can tell they use dummies. Look at the way their bodies move.
The Suite Life Goes Hollywood (2) - S2-E37
Revealing mistake: In the scene where London and Maddie fight and fall off the the saloon balcony, you can see that they are stunt doubles.
The Suite Life Goes Hollywood (2) - S2-E37
Revealing mistake: In the scene where Maddie and London come out of the saloon scratching and clawing, you can see that they're played by stunt doubles; the stunt double playing Maddie doesn't have any bangs, whereas Maddie has bangs.
Answer: Keep in mind, Muriel wasn't very popular. So the writers/directors must have thought it'd be a good idea to let go of the character. No one seems to be complaining.