The other jumps on him and declares that street-use rotors don't warp (in general). An Internet search bears him out, as MANY articles say rotor warp is a myth.
Googling, we find that brake torque variation is mostly from uneven pad deposition buildup (i.e., disc thickness variation) and axial runout. But then it gets confusing as the more enlightened sources begin to mention thermo elastic instability hotspots and breaking judder into low frequency cold judder and high frequency hot judder.
The heated discussion went on. And so did the confusion. For more than a few beers.
While we now know rotors rarely actually warp, does anyone know of a good scientific or engineering paper explaining the TRUE causes of brake related judder in street cars?