There will always be a
There will always be a risk, but if you know your course, it is probably limited.
When I ran shod, I would log about 90% of my winter kilometers in the dark. My usual Route is along the Rhein in Bonn. Most of it is partially lighted, but there are big stretches that get pitch black. Even the lighted portions are not light enough to see the small objects that I might avoid in the light. I have run the are so often, I know every centimeter by heart. But, what I will never know, is whether someone has freshly disposed of a beer bottle in such a way that no one will ever get the 8 euro-cent deposit back.
With winter approaching, I face the same dilemma. So far, I have tried running once in the dark barefoot. As far as sharp objects are concerned, it was no problem. Luck? I did hit a slightly skewed up cobblestone with my mid-foot. It left a handsome bruise in the center of the foot, but it doesn't hurt a bit. Funny thing is, even if I had seen it, I would not have thought to avoid the stone, since all the of stones in that stretch are skewed. I am thinking about a headlamp, but I doubt that it will light the way enough to avoid sharp things.
Give it a try, if you know your course well. Take along some tweezers and liquid band-aid. You'll never rule out the risk. But, if you can't relax while doing it, it is probably not worth it.
I am with TJ and the others on the pleasures of running in the dark. Some of my fondest memories of shod (minimalist) runs are a good 10km, in the dark of the winter night, about 5º C, no one else around, and nothing but the sound of the river and the tap, tap, tap of my own two feet.
Cheers,
Jamie