In my state, one must comply with any order from a police officer who is in uniform and acting in the performance of his or her duties. This is a law with criminal consequences.
My neighbour was 'arrested' by two men in police uniform, they later murdered him, burned his body, threw remains in the river and sold his car for parts. Him family only found out after the car parts showed up in repair shops.
You're in your rights too for sure, but given the semi-recent history of not giving a fuck 4th amendment along with how quickly the general public is to justify anything done by police officers I'd be scared as hell to do so.
That's an important distinction. If you're ordered to shoot yourself in the head by a cop, "no" is a perfectly reasonable answer, and likely to stand up in court.
I don't know which state you're in, but all the state statutes I've seen saying that you must follow a police order use the words "lawful order" in the text. Also many of them have limited domain such as "while on a public road" or "during a civil disturbance".
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.
I'm in California. In our state, it's part of the Vehicle Code, but courts regularly construe it as applying anywhere in public. I have personal knowledge, unfortunately, that violating the California Vehicle Code is in many cases a criminal and not civil matter. The statute doesn't include any qualifier that the order be lawful. I suspect that "and was performing his duties" is meant to cover that question, representing a legal fiction that cops would never issue an unlawful order.
For those who are interested in reading beyond Galpern, some other relevant classic cases are Terry v. Ohio and People v. Cohen.
