Right, so if that's not possible, then getting all of the music from a game when you enter that game (temporarily) isn't possible either. Now how would Badspot make that work????
*SARCASM IN THIS*
It's not temporary, you download it but can't access it on single player. The music files only work on servers that also have the music you've downloaded.
So downloading faces would possibly take more time than downloading music, which is already a lot of time. Let's say there are twenty players in a server, each of them having downloaded ten faces. That's two hundred additional files the player has to download upon connecting to a server.
Unless Badspot added the ability to check/uncheck an option to "Download Faces/Decals" similar to how you can choose whether or not to download music, textures, models, etc.