Are you aware of the automated "content-infringement" detection systems that youtube uses? If you post a clip from a movie or tv show that youtube has in its library of "stuff not to be infringed" then your video will automatically be taken down.
Yes, and often content is misidentified there too. I posted a anti-COICA video made with Xtranormal -- it was erroneously tagged as including content from Comcast Entertainment and banned outside of the U.S. (somewhat ironic, no?)