I'm still fuzzy on that term too. Where I'm from, "red nose" events are usually athletic activities held in the dead of winter (when just walking across a parking lot may be enough to redden an exposed nose.) In younger days, I finished 10th in a 2.7 mile "red nose run," mostly shielding my face by keeping my head turned sideways and a sweatshirt hood raised. As I was staggering toward the hot chocolate and donuts at the finish, I was stunned to notice a huge patch of frost where my breath passed over my shoulder. In any case, I gather this is all unrelated.
Regards,
messydom