Its during the unstructured circles that I find guitars very frustrating. People don't stop playing them, quietly checking out fingerings etc, so that you cannot find your key and then just I'm getting my breath one of them starts strumming loudly to begin a song and I'm out of time again and I still have to find my key the next time there's a pause. I'm still tyrying to find a way of gently letting people who won't stop singing that its time for them to take a back seat and let others sing. Any ideas?