On the way to work this morning, some guys were walking on the side of the road, rucking. Reflective belts location? On their rucks, not visible to the oncoming traffic they were facing as they walked.
All 3 bases I was stationed at required that on our road marches. Even in air assault school with a 20 mile march starting at 0400 we had to wrap it around our ruck. Though I guess if you wrap it around your waist the ruck covers the back part of it.