Two teenagers of color from a disadvantaged neighborhood sought my advice in how to respond to what they saw as police harassment: describing their most recent encounter as being "grabbed" and frisked against their will while walking in their neighborhood. What can you do to safely avoid unwanted contact with the authorities?
You have the right merely to walk the other way if there is no good reason to engage you. Avoid doing anything that gives rise to "reasonable suspicion" when there was none to begin with such as appearing to throw something away, running, or reaching into a pocket although none of those things are illegal. If an officer insists on making contact, do not do anything that can be considered a threat. Show your hands. Politely insist you do not give your consent to this encounter, do not wish to make any statements and want your lawyer.
If the police have reasonable suspicion you are about to commit, are committing or just committed a crime, they can justify a "Terry" (v. Ohio) stop: a brief detention to speak with you and pat you down for weapons. If anything illegal is discovered and you are arrested, you will have your day in court to challenge the police conduct as an invasion of privacy and freedom.
At the same time, gather information in the neighborhood of other similar cases of unwarranted contacts and file a complaint as a group and protest to the department and municipality. Good police work is one thing. Harassment is another.
