Well I often use fur as grass in my architectural renders. Aside from that, I remember once I applied a glass texture in a window and it looked black in the render, then I flipped the polygons and nothing happened, it still looked black, but as I said before and as you think, it is not a priority. Some rare times the shell command cant handle some surfaces and I leave it as surfaces and if there are a lot of surfaces its hard to predict which are which side, but it is not the day to day situation.