Why do people think it's okay good to blend into the night when they're out on their nightly stroll?
So that no one can see them of course.
I frequently work late, leaving work past 9 pm, but even if I leave earlier I'm usually riding home 10 miles in the dark. Some of the places I ride through are not the best neighborhoods.
On my ride, if I have lights or reflective strips, they should spell out the word "V I C T I M", in those neighborhoods I prefer to not be seen from a distance, I can avoid cars since I can see them, you just have to make allowances for the fact they can't see you is all. Plus, without lights, you have to ride slower.
Other places less worrisome I'm running a flashing tail light and a headlight.
I believe that the element of surprise saved me on one occasion when I was pursued for a short distance by a miscreant on foot, he didn't have time to prepare in advance on account of he didn't see me coming.
And a funny story, sorta related to my point.
A friend of mine is an SAPD Cop, bicycle unit. Several of them are bike loonies. Being a young guy it is not uncommon for him and four or five of his friends to get off of their downtown shift in the early hours of the morning, get on their own bikes, and ride a long loop around the adjacent poorer parts of this city. They wear the usual civvie cycling gear, helmets, reflective gear and are well lit-up. Firearms discretely carried about their person.
One night a guy in a passing vehicle, not dreaming these guys were Cops, threw a large beer bottle, striking one of the riders and causing him to fall off. Loud shouts were exchanged.
Then the offending vehicle actually turns around, and the two guys in it actually get out to pick a fight with what they assumed were a bunch of pansy-a$$ed cyclists.....
...shortly thereafter of course they found themselves laying face-down upon the pavement, hands out to the side, while colleagues of the cyclists were summoned to the scene 
Birdwatcher