Deliberate mistake: In the butter skating scene, the boys signing Paisley's cast are not writing anything. They are just pretending and their pens don't even touch her cast.
Revealing mistake: When the students see themselves in the TV, (which meant that Skidmore was watching them because Chyna had given her a hidden camera) you can see in the TV that there is actually a green screen on the screen and the video is not actually playing, it was just edited in later.
