May I take issue with that comment? Admittedly, black was on the old master's palettes...
Sam, you are absolutely right. I was oversimplifying to emphasize the color that Cezanne uses to model with, which was a new concept at the time. Black is better when made with such combinations as you suggest, and I myself never use just black (or just any color). I mix a range of colors at all times; it gives greater depth to the color.
Michelangelo actually reversed this warm in foreground/cool in distance color formula in the serpent on the Sistine Chapel. His use of color blows my mind. He's incredible: as a painter, sculptor and as an architect. Definitely the best artist ever. (Ooops, did I, the abstractionist, actually say that?) 
Notice how, on the serpent's tail, the green is foremost and the yellow is in the back. Amazing.