That's a very interesting link Joe gave. Some of it is very refreshing:

Because the meeting between Seeger and Plenn took place almost forty years ago, neither Plenn nor Seeger has a precise memory of what words were spoken. However, the testimony of both makes clear that when Plenn taught Seeger the Song, she communicated her authorization to publish it, without placing any restrictions on that authorization. Plenn taught Seeger the Song in the hope of keeping it alive; her hope was that Seeger would sing it, record it, publish it -- whatever would keep it from becoming forgotten. She testified as follows:

Q And were you aware that Pete Seeger was going to be publishing this song in Sing Out as part of --
A I hope so. Well, I didn't know he was going to be publishing it in Sing Out, I hoped he was going to be doing something with it; sing it and record it. That's why you give a song to a folk singer, is it not?
Q Yes. And that was okay with you that he would publish it?
A You want them to be alive.
Q And that was okay with you that he would publish it; correct?
A Uh-huh.
Q Yes?
A Sure. Indeed.
Q You testified also before, you said Pete didn't have to ask me for permission to publish the song in Sing Out.
A No, No.
Q Is that right?
A Indeed. Certainly he didn't. It was a gift freely given with the hope that it would be kept alive.