I can't be considered an expert either, but from what I understand they're currently using spherical harmonics (or some others set of basis functions) to model how a surface emits light from various directions.
However in most cases this will simply cut off as soon as you view a surface from the other side, so it kind of makes sense to add some special handling for that scenario. Especially since it can be hard to properly fit a discontinuity like that.
As it currently stands I imagine the reflection trick would be unable to work if you had a camera view from the other side, which is not ideal.
Oh right, because if we're looking at (say) a ball from two sides, we're not looking at the same splat. So except for very thin 1D-approximating shapes like the spokes of a bike wheel, or pointy convex shapes, most splats will effectively be domes, right?
However in most cases this will simply cut off as soon as you view a surface from the other side, so it kind of makes sense to add some special handling for that scenario. Especially since it can be hard to properly fit a discontinuity like that.
As it currently stands I imagine the reflection trick would be unable to work if you had a camera view from the other side, which is not ideal.