I am amazed people still use that type of modeling, and I can't even remember the 2002s. Yeah, sure, you will save like 6 polygons per wall, but, people, c'mon, nowadays we have so much ram we could fly to the Moon and back! :D
I tend to see this problem in such manner: If it's physically correct render engine, then you should physically correct model your scene. Just like the example with the correct modeling of a glass and a medium inside it - there has to be at least some amount of thickness. Judging by the fact that Indigo is a physically accurate render engine, and a very accurate one, I would think it actually does worse with such tricks with thin walls, glass, surfaces in general, then the biased ones. But, hey, it's just me, and it could actually be an accuracy problem within engine, who knows.
It's time to deliver that sweet 0.48 magic, guys! :D
I think you infer too much from what I said...