Coincidentally a fellow approached me in the grocery store parking lot a couple of nights ago to ask about my helmet flashers. He wants one for walks with his wife in their rural hometown. They wear reflectors but said cars don't seem to notice and still pass too closely even when there's no traffic and plenty of room to go around.

I often see folks walking with their dogs in the evening and many of them do wear some reflective bits - bands, strips, dog collars, etc. But with my bicycle headlights I find them hard to see unless the light is pointed right at them. The headlight on my helmet is relatively directional, compared with the less bright but non-directional front light I used to use. The less bright, non-directional light was actually more effective for seeing reflective surfaces - people, signs, vehicles, other cyclists.