In its defense, the EM songbook is huge, and was bound to contain some errors. The website listing the errors is maintained by Peggy Seeger, as a means of addressing them. it seems to me she is being more responsible than most editors! Also, some discepancies may reflect differences in the "official" verses as published, vs. the way EM actually sang the song after it was in his repertoire for a while. To paint it in broad strokes as unreliable may not be fair.