McGrath of Harlow, What are you referring to when you ask how they would know that? ...that is has nothing to do with roundhouses, or are you wondering about their slang definition? The liner notes are credited to a Norm Cohen of Portland, Oregon,and there is a credit to Bob Pinson at the Country Music Foundation for discographical detail. I suppose with folk music you never can be sure of anything, and mishearings are entirely possible, along with all the other things that twist songs over time.