I think it would be a little safer for when you make videos showing tv episodes or music videos even, to put something like this: "(Name of movie/episode) is copyright to (Owner of Movie/episode) and i do not it's characters, songs, or anything invovled with it. in the beginning of your video or something that will make sure everyone who watches the video will see it. And maybe they're deleting the fan videos because you're not sending a big enough message of the copyright owners, OR they're removing them because they have scenes or such from movies, episodes, etc.