I still fail to see how a border morris dancer in full fig could be seen in any way as a caricature of a black person.

The point is, the minstrel tradition is the only context in which most people in this country have seen anybody blacked up for entertainment purposes. So whether you put a blacked-up white man in a tatter coat, a suit and tie or a spacesuit, those minstrel associations will still be there. The only people for whom this won't be the case are people who have seen more blacked-up Border Morris than they have blacked-up minstrels - and I venture to suggest that there aren't very many of those, outside the ranks of the BM dancers themselves.

Now, take that same white man and dress him in "full fig" - but leave off the face makeup, or paint his face some other colour (green, blue, white, whatever). Does he look blacked up, with connotations of the minstrel look? No. Does he look the part of a Border Morris dancer? Yes.

So what's the problem with simply not using black?

PS Why did Richard the Lionheart get irritable when he saw Blondel coming to sing to him?