Well technically I dont think that there is soooo many of such people in the game. I mean its a paid game after all, its surely not expensive to pay sub for each month, yet still, the MOST COMMON way there is, is that people have a job from 7 am to 4 pm, or go to school till 1 or 2 pm, them come home.
From my experience people who work on shifts are factory workers and I don't think we have them playing the game. Sure you have doctors, firemen working on shifts too, but I just dont think those are the kinds of people playing the game