One good example of the nonsense...
Brake Tech - Brake Rotors and Track Use
"Slotted, drilled or dimpled rotors offered as OEM replacements
should not be considered appropriate for high-speed track use.
While grooved, drilled and slotted rotors offer an enhanced appearance and add some resistance to the boundary layer of gasses that can build up between the pad and rotor, they are not designed to withstand the extreme temperatures that are produced on the racetrack. If they are used on the track, it is very important that the rotors be carefully inspected and should not be driven on if even minor signs of deterioration are seen. Note, too, that if these products are used on the track they are not warrantable."
