I've an all-45g HHKB, and I sometimes make accidental presses when Im typing on it after extended periods of typing on a stiffer board. Usually it happens when Im resting my fingers on it, and I accidentally press too hard. Then again, after using the Topre for a bit, I stop doing that.
I don't really believe in the idea of people being "heavy typers" - it's all just muscle memory relative to what your hands are used to. If I type on a Topre for ages, buckling springs feel very stiff. If I type on buckling springs, Topres feel too light. Continuous typing readjusts your hands to the required force.