And in the youtube terms of service there is (or atleast was) a part, according to which there is no guarantee that the viewer will see the content as it was given by the person uploading it. 
As in if youtube wanted to, they may at will modify the content into needs suitable to theirs.
Mostly assumably such is meant for the prosessing and packing of the vids, but it leaves a loophole for them to be modified or altered into anything.