Not so much how it looks but how it sounds as if it might look, surely. Which is the point I made in a post way back up the thrad:

"I would suspect that it's the idea and not the reality that's the problem. Say 'black make up' and the image people have is of performers dressed up and behaving in a way that parodies black people. Which in this case could well be the image likely to be conveyed by children to their parents, which teh school was worried about.

The reality of blackface, whether Border Morris style or Rochester sweeps, is very different, and I very much doubt if many people coming across it in its natural habitat, the street, ever see this as being anything to do with parodying black people."

Context is important here - and dancing in the street is different from performing in a school. Motley Morris would have done well to take note of that, and pick a different colour for the occasion to avoid misunderstandings from parents who had not seen the dance when kids went home and talked about it.