Just came across something that I had to share because it really highlights how weird copyright/public domain issues can be...
I subscribe to "PDHub," a Roku channel featuring public domain content. This week they started putting Christmas stuff out. One of the things they have is "Santa's Ninth Reindeer," which is Rankin-Bass's "Rudolph the Red-Nosed Reindeer." They claim that the original RB special had an invalid copyright notice, making the special (technically) public domain. The powers that be got around this by copyrighting the soundtrack. So someone took the special and either (where possible) stripped out the copyrighted music or (where necessary) replaced it with public domain recordings of other Christmas music, creating a "new" special with a new name! The whole situation just amazes me.
Actually, I recall hearing a while back that something similar happened with "It's a Wonderful Life." The movie was originally such a flop that the studio let the copyright run out, which is why it started be broadcast by everyone and his brother every year at Christmas time. Once it came to be considered a "classic," the studio regretted losing the copyright, but found a way to "reclaim" it by copyrighting the soundtrack separately. So, apparently you can show the movie as a silent film legally, but if want to use the soundtrack, you've got to pay royalties.