Regardless, most pilots realize well before 100 ft that they won't make their target. If they're on airspeed, as they should be, raising the flaps won't cause a problem.
So you would rather teach a student to increase the angle off attack at low level instead of teaching them to lower flap when they know they can safely make the landing spot (see the thread re:flap on base), purely because this upsets the trim of the aircraft?? You're nuts pal. Aircraft stall when the critical angle of attack is exceeded - not at a given airspeed.
VFE.