I have noticed hi viz helping, especially during low light times. For a while I wore dark colors, but when I switched to hi viz I noticed people jamming on brakes a intersections, driveways etc. maybe they think I'm a cop? Either way, I don't assume they see me, but it only has to make a difference once....
'12 Tenere, '04 Tiger, '09 WRR, '06 DRZ, '06 TW, '01 250 EXC, '09 KLR