Why do dealers lie so much? They sound like politicians! Rotors warp because of too much heat and bad torque from lug nuts. They don't warp from parking! Even when there is a lot of rust build up, that doesn't cause warping. The rust will fall off after you use the brakes the first time.
If sitting ruined brakes, disks would have been pulled off the market decades ago.

Klaus
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98 V70Rawd(101Kmi), 95 854T(85K mi), 88 245(165K mi)