It's been a while since I made any reference to this case. I found myself not all that convinced that what was at stake for Thicke and Williams was whether or not a style can be copyrighted. Looking at this as a guitarist who plays classical guitar I don't come to the debates around this case as someone who's making work that is in a genre where a super-majority of the available work is near or after 1970s copyright law changes. Classical guitar has a huge body of work that is, very often, public domain. Critical editions come along with notes about left and right hand indications but that is a point of editorial expression more than the ideas that are comprised by the notes on the page in handwritten manuscripts or engraved publications from the 19th century. I.e. the ideas vs expression continuum hasn't gone away and for classical music the issues don't come up in the way they might more readily emerge in a style like hip hop or other popular styles. The intellectual property issues for taking ideas published in scores by Sor or Giuliani and recomposing them into newer styles are not the same as a few musicians encountering allegations that they used Marvin Gaye's work to build a song.
The more recent statements from the court, as reported, mention that the issue of access could be considered comparatively moot in the case of work by Marvin Gaye. To unpack that a tiny bit, in cases regarding plagiarism one of the things that has to be established is that the alleged infringer had access to the infringed work. The court basically said that the bar was higher for a musician as famous as Gaye than it would be for someone far more obscure, which is to say that Gaye's music is sufficiently universal in terms of whether you or I might hear it in a store or a public space that the burden of proof that the defendants couldn't have heard Gaye's work is a bit heavier.
I have to admit I haven't felt all that bad for these guys. I don't really like the song, now that I've finally heard it.
But that Marvin Gaye's estate and lawyers could be seen as the bad guys in all this was an interesting discovery to make. Does this throw a monkey wrench into some elements of debates about cultural appropriation? Not sure that it does because I'm not sure the cultural appropriation debates are made ientirely in good or bad faith.