i've been looking at the idea of ball cap with surface mount LEDs under the bill of the cap, but i'm not much of a cap wearer any more. i then thought if they can fit cameras into sunglasses, why not do the Orbital thing with bright LEDs attached to my sunnies? then, the evil grin comes out and starts thinking more sinister with lasers to not just ruin the shot, but the sensor itself. then i realize, i've got work to do, and forget the whole thing
If you mean the retroreflective stuff, that's because it requires a bright flash to work. Modern digital cameras now are generally good enough to not require flash for a good picture, even in low-light conditions, so paparazzi don't use them near as often.
Clothing or accessories that shine IR are a completely different functionality and while they could be stopped by paparazzi buying better IR filters, that requires an additional cost on top of the camera