I run daily, training in a suburban area with poor sidewalks. From time to time, I'll encounter a pedestrian going in the opposite direction. The sidewalk isn't quite wide enough for us both to pass, so one of us has to move to the side. I'm typically the one to do it; I'm moving faster, and so I'll spend less time in the street, near cars, than the other person. About half the time, the street is a busy one, and half the time, it's quiet. Additionally, if the other person is a dog-walker (or a parent with a stroller), they need a very wide berth, and shouldn't have to bring their pet/child onto the street.
Here's a typical diagram of the situation (green is a small grass strip, grey is the pavement, and black is part of the street; assume that all parts are flat):
I have some friends (also runners) who disagree, stating that it there's no inherent reason for the runner to be the one to move, ignoring cases of dogs and strollers.
I'm wondering what the general etiquette is in the running community. Extenuating circumstances of some sort notwithstanding, in the case of a runner and a walker, is the runner expected to move onto the street unless the other pedestrian does otherwise?