It depends on how wide or narrow the IES is, as to whether it reflects or not. So it would seem to be similar to the Prevent Black Appearance for the direct visibility (that is, since the IES is narrowing the directionality of the light, it may be so narrowed it doesn't show up in reflections).
Interestingly, it can show up in reflections of reflections even when that first reflection doesn't show up to the camera (presumably due to how the angles all inter-relate - scene attached but you'll need to add your own IES, I was using the ones that come with the Corona install).
I can't say if this is physically correct, expected, or a bug at the moment. A workaround in any case would be to have two light sources, one to cast the light, one to show up in reflections.