The "lazy fingers assumption"

I've coined the term "lazy fingers assumption" to refer to a principle that can be used to analyze tactical bullet voting under voting methods that satisfy the later no harm criterion. The idea is that if a voter knows that adding a ranking has literally 0% chance of altering the election (i.e. the voting method won't even look at that information) then they will not add that ranking.
Under the lazy fingers assumption, in IRV, any voter whose favorite candidate is one of the 2 finalists (and the finalists were foreseeable) will bulletvote.
The opposite assumption is the "expressive voter assumption", which assumes that voters will add rankings despite knowing that it has a 0% chance of affecting the election.