What are the laws on using copyrighted material in mixes do you know ? I know Sound of Monte Carlo's soundcloud (they uplaod monthly mixes or w/e) is about to be taken down, they do use copyrighted material in their mixes though.
In the UK, where Soundcloud is based, it's very similar, except the equivalent of "fair use" is called "fair dealing" and it's much more restrictive in scope.
My point is that the laws don't stop the people doing the "infringing". We don't care. Its the businesses that could profit from the human need for creativity that are hurt by the absurd situation.