Axeman, why bother with a second camera just for a HUD? Surely that's all flat surfaces (i.e. quads or sprites) anyway, so Z-order shouldn't matter..
While his example is probably not the best in the world, his reasoning is still perfectly valid. He explained in his post that the reason for doing this is to get non-convex shapes to work. It is unfortunate that his example code doesn't contain any, but that wasn't the point of setting up a second camera.