In the "refuse to move on after police asked you to" scenario here, the NYC case "People v. Galpern" is often used as precedent. In that case the defendant was found guilty simply because he was, in the officer's view, obstructing the sidewalk. He was not otherwise disturbing the peace. From this case, the courts tend to side on the judgement of the arresting officer unless there are extreme circumstances.
For those who are interested in reading beyond Galpern, some other relevant classic cases are Terry v. Ohio and People v. Cohen.