I play for Bollin Morris in Cheshire and we tend to use a mixture of colours as well as black. To my knowledge (I haven't been with the side for very long) no one has objected to the black faces as yet. Of course it's entirely possible someone may be offended and not say anything, but we would quickly point out the tradition of disguise etc should anyone question the practice.
With some people however you just cannot win - on Friday evening, sitting in the pub in full regalia after having danced (and with a very blue face I might add) in the car park, I was accused of being racist simply because I said I like English Country Music because it put me in touch with my heritage! I began by stating that I did not wish it to sound nationalistic but alas to no avail. It seems that to some people you must like all kinds of music or else be seen to be racist.