You can see knee pads on Raven's knees when she is scooting along the vent.
When Alana is putting the cheese wrapper in Eddie and Chelsea's locker in Raven's vision, you can see that it's been taken by someone from the inside of the locker.
When Loca is standing on Raven to push Alana up in the vent to plant the cheese, if you look close, you can see that her feet are not on Raven's back, but rather on a flat surface that must have been erased by the computer.