Did he specifically say he wouldn't because of the content, or is there some other reason?
Reason I ask is that graphic designers do work every day using copyrighted materials legitimately, and I can't imagine that they would have to "prove" they have a right to use the media in question. What are we supposed to do, carry a "license" to authorize print shops as to what they can or can't print??
Might want try again at another location. Just say you were hired to design it.
~Ray B.