Didn't know the brakes get hot enough on a trackday to glow red hot, but these pictures from the Renaultsport trackday at Brands prove they do.
From this article: http://www.channel4.com/4car/road-tests/4Car-fleet/renault-clio-trophy/report01.html
From this article: http://www.channel4.com/4car/road-tests/4Car-fleet/renault-clio-trophy/report01.html