I think the comments on that video were very interesting, so much so that I didn't hold back, but joined in :) apropos to that, one of the commenters does point out that there was no essential difference between these kids and the average kid with a pumped-up ipod polluting the sanctity of the soundscape, so we have an issue here, is it holding back, or a holding on to that previously sacred space? What if these kids sang in the library, just before exams, or in a medical operating room ... clearly there is an issue of gleeful abandon wandering into wanton belligerence ;) We encounter this all the time, of course. A band may have one member who wants them to spike their hair and add some thrash guitar to "get with it, man" whereas the others quite like the income of their wide-lapel blue-velvet suits and the polka repetoire ;)