Yeah, my apologies, I meant the ball-cap clip. You're right though, it's the flatness. My lenses do have curved fronts, so I did some testing with a flat transparent plastic surface, and the extra reflections were all over the camera. It might also be a factor that my lenses have an anti-reflection coating for greater light transmission, but I don't know how far into IR that works - and most transparent materials are 90% or better reflective in the IR spectrum.
Track-clip (the powered one) for you!