Wow! That’s one freaky image. Very impressive though.
Anyway… I’m certainly no expert, but, I think that basically means he relies on using only the reflective properties of a material to achieve the specular highlights instead of using any “fake” specular properties. I’ve seen a lot of arguments about how speculars should be achieved, but I think it basically boils down to how anal you want to be.
In blender you would turn down the specular settings on materials and attempt to create them using only the ray mirror settings. Don’t think it has much to do with radiosity. I could be wrong though.
Hope my limited knowledge helps a little