To avoid paying this 'tax' (that's what it is) I am that driver on the 100kmph freeway doing 98kmph as indicated by the car GPS, car dashcam GPS, phone GPS and speedo. I have this modern high tech device in my car called a 'cruise control'. Pretty simple in 2017 to get at least 2 reliable data points to check your actual speed settings.
Oddly enough it works in 80, 60 and even those tricky 40 zones.
