It's easy. If your aim is entertainment, you'll do whatever is required to entertain. That may or may not include folk. If you want to do folk, there will be some point (which will be different for each performer) that you don't want to pass. Read the History of the Excluded Myddle, by Richard Gough, or reflect that when you look at a rainbow, there is no point at which one colour changes to another. Therefore all colours are the same.