I think you're right when it comes to quilts with "blocks", especially after seeing Jenny Beyer's block book and Barbara Brachman's book on applique. It seems like everything should say "based on a traditional pattern."
Now, with art quilts... there's the originality.
I don't particularly want my tax dollars going to the copyright/patent office to license quilt patterns of iffy origins, Oops, is this too political for the forum?