Thanks for the link to Twenty-One Years. I read it through, and started laughing again - another song (or variation) where the man's in jail, presumably because of a woman, but why? What happened?

Which is pretty reticent, for a folk song, when you consider others, like Long Black Veil, where the guy dies because the girl can't give him an alibi, or Banks of Ohio, where he stabs her with a knife, or any number of others where the grisly details are spelled out and not just hinted at.