This is borderline off-topic, but it came to mind and I thought I'd share it anyway.

Myself and another producer where shooting a video in the Wind River Range. We needed a shot of a signal mirror reflecting in the distance. I dropped him off on a roadside ledge with the camera and a view of the opposite ridge.

I got in the car and drove to the other ridge, maybe a half-mile away and got some gear together. By happenstance, I pulled out an all-weather blanket and jammed it on the outside of if my pack under some bungee cords with the shiny side out. As I scrambled up the slope I created intermittent reflections from the blanket that marked my movement.

I found a location and started to signal with the mirror. We caught some of the reflections on camera and used them in the program, but it wasn't quite the shot that we had hoped for. When we discussed the shot later, he said that my movement up slope with the reflections from the blanket on my pack was more visible than my stationary use of the mirror. When I wasn't moving and without any reflections, I pretty much vanished from sight.

I'm not quite sure how this relates other than, at a distance, anyone can be hard to spot and movement has a lot to do visibility.