Do recipes which measure flour by volume assume that I'll sift the flour?
In all the recipes I've followed with a cup measurement (volume) of flour, it is unsifted. 

From what I've read, if a recipe calls for sifted flour there's two ways to do it:
If it calls for "sifted flour" you sift the flour first, then measure it.
If it calls for "flour, sifted" you measure first, then sift it.