Greg, I think you are confusing Lucy Wan with Polly Vaughn or Molly Bawn or whatever. The latter ballad relates the story about the accidental shooting of a girlfriend as you said. Lucy Wan (Child #50, Lizie Wan) is a classic incest ballad. In it a young man kills his sister after learning that she is pregnant by him, the result of a presumably consensual relationship. No apron there. The Setting of the Sun is of course the accidental-shooting story.