Using the same tune/melody is one thing. Woody did it, the Pogues did it, many a folkie does it. Folk tunes are generally simple things. But we are talking about an intricate guitar ARRANGEMENT here, not a melody. That is not the same thing. Woody used a lot of tunes that had been used by others, others who may have penned them or borrowed them themselves. Time-honoured. Find me a Woody ARRANGEMENT that he stole note for note from someone else that he failed to acknowledge and I'll admit that I'm wrong. I'm honestly not that bothered about this, but I am bothered about people not being truthful. And the truth here is that Nic invented a superb guitar arrangement to accompany his singing of the song (not stolen from anyone else), and Dylan, without acknowledgement, lifted the arrangement almost (OK, HiLo?) note for note, chord for chord. The very definition of plagiarism.   

I'm wringing my hands here, banjaxed by the inability of respectable members to admit mistakes. I've made mistakes here and I admit to them and apologise if necessary. I mean, cor blimey, Joe...