A point that's often missed is the ambiguity of copyrighting arrangements. If the performer specifies that it's on;y the arrangement that's being copyrighted, well and good. BUT..that doesn't help when Oscar Brand holds a copyright on Yankee Doodle and Pete Seeger holds one on Cindy and Woody Guthrie's estate claims "words and music" for everything he wrote. When last I looked, there were 14 distinct copyrights on Barbara Allan.