I agree with you, Joe, that as a practical matter, it pays to go along with Hal Leonard, but the fact is that they do not have the copyright to the melody or lyrics of any public domain song. The accompaniment, perhaps, if anybody ever pinned it down, but not the old work itself. When pressed on this simple matter, they refuse to discuss it. A bully's technique.

I have before me a copy of their 'Hymn Fake Book.' They claim to have copyright in a song called 'God Moves in a Mysterious Way.' It was first published in 1635.

On the next page, we see 'God of My Life,' a traditional Scottish melody arranged by someone who died in 1872. HL claims copyright in that. On page 151 they claim copyright in 'Wie Schoen Leuchtet,' composed by Philip Nicolai, who died in 1608.

Hal Leonard Co. may have added chord symbols to these melodies, but chord symbols cannot be copyrighted. (Not to mention that others have been using the same chords for centuries.)