Following Lewis, we can say that in the US there is a convention to drive on the right, and in the UK on the left. But what should we call the situation that exists when walking in crowds? For I have noticed in each country that there is a tendency, albeit fairly weak, for pedestrians to follow the convention for automobiles: in the UK, pedestrians tend to shift leftward to avoid collisions, while in the US they tend to shift right.
What is the right way to characterize the above? Is it a convention at all -- a weak convention? -- or just the shadow cast by a genuine convention?