They are not intentionally lowered (out or down) for that occasion, but :
One carrier I know parked the night stop aircraft and left them with flaps down when there was a frost warning so the de-icing contractor (with prior approval from the carrier) could complete an early de-ice subject to prevailing conditions and hold over time. This negates the need for the engineers or crew to position the flaps as they are already in position.
I believe the flaps should be down for de-icing to ensure total coverage of leading edge and upper surfaces . . . but I may have made that up and stand by to be corrected
GA