Continuity mistake: In "Broke 'N' YoYo", when Cody has just sat down to talk to Zack after collecting loads of towels, in the first shot the towels are on the chair in front of him. In the next shot, when Cody leaves to practice, the towels have vanished. And in the next shot, when Bailey and Zack are talking, the towels are back again.
Revealing mistake: In the final scene where Cody is in the finals for A Yo-Yo competition, Zack's towel gun (which he uses to get towels to people) malfunctions and sends towels flying. Look closely and you'll see that the number of towels in the gun is not decreasing. It's obvious that the flying towels are fake.