They could've averted copyright issues by having the characters be fans of future entertainment works and genres. Well, their past, our future. What bugs me is how there's never any sign of human creativity from later than the year 2000, beyond the occasional holonovel or Jake Sisko's writing. Why is nobody a fan of literature or music from the 22nd century, say?
Yes i've thought this before, how hard would it have been to make up a band name or an author's name. Or maybe the TV writers were not allowed to?