There seems to be some misunderstanding about the ice protection of the Q400.
The procedure calls for "increase ref speed ON" in icing conditions. That switch nor only changes the AOA where the stick shaker starts. It also changes the red tape warning of the stall speed area on the speed tape.
So when you switch on "speed increase" you always have a very visible reminder on your speed tape indicating the now higher speed where the stick shaker will set in.