I wonder what the grey areas are. When I workout I listen to a lot of personal development videos which is like Jim Rohn and Les Brown and Tony Robbins speeches with movie clips playingin the background. Not sure if that is blatantly against policy or if its okay since they've essentially tied that all together does that make it a new work of art?
Another thing I see that I think is blatantly just trying not to get caught is you can watch some TV episodes on Youtube but they will make a small screen within a background, I'm guessing whatever system Youtube uses to catch duplicate content can't pick up a frame within a larger design.