Interesting concept... so... on a bright mid-summer day, one can avoid sunburn if they move about? Don't mind my skepticism. However, the darker the skin the more natural protection is afforded. Aboriginals have the equivalent protection of a white person wearing SPF 40 sun blocker. A friend, who is quite dark, burns almost every spring, but there is little reddening of the skin to indicate the burn, just discomfort. Black skinned people suffer skin cancer, but at a much lower rate than whites...