There's no peleton to speak of on a fast or tricky descent. You may have small groups of two or three working together on the more controlled parts of the downhill but that's it. Being good at descents is about aerodynamics, reading the curves to take the straightest route possible, braking only when you have to and just having nerves of steel. I've gone down hill max 34mph and get scared taking a gradual curve at that speed. They're going a lot faster around some nasty curves!