Currently in jEmplode 42pre3, soup playlists never appear to be dirty (even though they actually could be). However, if soups were updated, you will receive a warning that you need to sync before quitting (i.e. things actually are dirty, but it just doesn't look like it in the UI).
Does anyone have a preference? I tend to like it not appearing to be dirty. In fact, I've been considering making it so soups don't even cause the "warn on exit" to occur (basically, if you sync, they'll be fixed up, otherwise, they are ignored).
Mike