I'm a couple of days late on this response, but that comment about altitude playing some part in rotor warpage does not surprise me.
I lived for three years at 7500' and routinely went up to 12K' and even 14K'. At those altitudes, one would expect to lose engine power - and you do - but what I found surprising was a loss of cooling capacity. Lower atmospheric pressure means less air molecules per volume, and a resultant loss of "air flow" across your radiator cooling fins.
It is common to see a slight increase in engine temperature while climbing, but until I stopped and idled for a while one day, I always thought the increased temp was because of, well, the climb! But idling will cause some trucks to overheat even though the radiator fan is spinning away, blowing what little air there is over the radiator.
If you don't believe me, read some of the race reports on the Denver CART races. Not only do ground effects have less effect(!), but radiator area needs to be increased just for races at higher altitudes to keep the engines from overheating.
Well, back to brake rotors. Although my time there was officially "pre-LX470" and I was still an "LC-wannabe", I drove a K blazer and had to grind the rotors once and then replace them a year later. This was the same amount of rotor maintenance in three years than I had needed in the previous 10 years of ownership.
Maybe you think it was just Chevy brakes? Unfortunately not. While living there, I bought an Audi S4, Audi's answer to the BMW M3. Front rotors are something like 12" or 12.5" in diameter. MAJOR braking power. At my 20K mile service, the front rotors were ground to take care of warpage.
No, I don't "ride" the pedal, and I don't "ride" my brakes downhill.
Higher altitude = lower atmospheric pressure = less air results in less cooling and higher temps.
Counterpoint?
