Bicycle rider with a somewhat weak top-of-helmet mounted light (maybe 100 or 200 lumens): I have a tough time telling if it's on while riding if it's somewhat bright. Zero impact to view.

Can really help with retro-reflective signage, since I can point a light directly at the sign. But definitely not a blinding return.

I use a 300 lumen one, and it's the same, reflection is just not a problem at any reasonable distance (like over a metre)