I agree with that too, Matt. However, the phrase you used, "you can call it folk if you like - most people do", does complicate issues. If someone who believes Milford and Sons to be folk and go into a folk club expecting to hear that music, they may be disappointed. They may be pleasantly surprised too of course:-) Worse still, if a youngster learns a Mumford song and plays it at a folk club they may received some hostility from died in the wool traditionalists. That is where some guidance may be needed.