Worked like a charm, thank you. I searched but never came across that post.
Left - Original: Notice the glow behind and beneath the sphere from the emission.
Middle - Custom node: Glow is fixed, but the reflection is still too emissive at the base, this effect could be nice for fake caustics but bad for a metal ball.
Right - Custom Node + Occlusion Mask: A simple gradient to mask out emissive near the base of the ball. Some kind of distance field gradient may work well here too.
Edit: Nevermind on the distance field gradients - it appears neither the surface cache nor hit lighting reflections display distance field outputs. You can see my attempt at using distance fields as a mask below. The reflected ball does not have any distance gradient, making it impossible to use as an occlusion mask. Bummer.
