Harry Potter and the Prisoner of Azkaban - No Feet?
When Harry is making fun of Malfoy by dragging him by his feet down the snowy hill near the Shrieking Shack, you don't see Harry's foot prints! Even though Harry is invisible, his foot prints should show up! Later in the movie, Harry is seen with the invisibility cloak on again, and his footprints DO show up in the snow.
I respect your careful looking, but there really wasnt a lot of snow on the ground near the shieking shack. If you go outside (when it has just snowed lightly) and walk on it lightly, you can't see your footprints very well. Also, depending on the angle of the camera, sometimes you couldn't see Harry's prints because Malfoy was being a wuss and flailing his arms and legs every which way and that.
THIS IS FAKE!
From moviemistakes.com:
If Malfoy is being pulled that means Harry is in front of him pulling him behind his back, in which case Malfoy's dragging marks would cover up Harry's footprints