Nope, the soundbridge doesn’t do anything with the compilation flag.
Which is kind of strange… It’s hard to read between the lines of Roku’s NDA’d statements, but he seems to be saying that there isn’t a way to ask for the compilation flag, but there sure is — it’s daap.songcompilation. I’m not sure what he’s getting at in his answer.
Anyway, you’ll find that when using iTunes against mt-daapd, you’ll see compilations expressed correctly, but not with a soundbridge as a client.
That’s a soundbridge thing, and they are aware of it.