Another effective tactic is to simply walk past the officer saying “I do not wish to be encountered”. If he wishes to stop and DETAIN you, he must affirmatively do so, putting the cause and justification on him.
That doesn't work with a traffic stop because you are technically under arrest in most states and the way you are released on your own recognizance is to sign the citation's "promise to appear” line.
That’s a new one on me. I’ll have to remember that.