Or the ground being low traction: dusty/dirt/wet. Harder to control what you land on, but will diminish MIPS’ ROI in many situations.
If ruling out risks by a priori is a solution, why wear a helmet at all? Maybe you won't hit your head when you fall. Maybe you'll land in water or on a satin pillow (low friction).
If ruling out risks by a priori is a solution, why wear a helmet at all? Maybe you won't hit your head when you fall. Maybe you'll land in water or on a satin pillow (low friction).