Reflective Scarf
... ruins unwelcome flash photography. Now that is a useful gizmo! It's really expensive, but it's based on something already common: a bike reflector. There is reflective clothing for night joggers. I am now wondering if those reflective jackets, hats, tape, etc. would similarly foil photography. Or for that matter, jewelry made out of bike reflector material, which is quite cheap and not that dissimilar from some pop jewelry.
EDIT 2/10/19: Reflecitve clothing is already available for safety purposes (see discussions below) and would likely foil photography as well. This company makes reflective vests including some that disclose disabilities.
EDIT 2/10/19: Reflecitve clothing is already available for safety purposes (see discussions below) and would likely foil photography as well. This company makes reflective vests including some that disclose disabilities.