I think Burl should answer this one. When I knew him in the early sixties Burl carried a guitar case when he played at my club. He never opened it on stage, infact he never got a guitar from the case, He always sung unnacompanied. When I asked him why he never played his guitar he told me the case was full of shirts, underpants and socks and other traveling gear, he said, "But if you are a folk singer you just got to carry a guitar case"
Bill