I've done plenty of hard trail braking into turn 2 (Andretti hairpin) @ Laguna Seca, and with DSC off, I've never noticed any undesirable braking. Everything was at my control it seemed
My guess is just the dynamic brakes effectively hugging the pads closer to the rotors in case you need to panic stop. I doubt it's that rain swiping feature, since I recall that the windshield wipers have to be triggered for it to be in effect.