Good manners are for all of the time and people who have good manners are not mistreated by the police. Why isn’t anyone asking why Michael Brown didn’t stop walking down the middle of the street and relocate to the sidewalk when so requested by the policeman with a gun? Didn’t his parents have the talk? Did they leave out the part about “If a policeman asks you to stop jaywalking, stop jaywalking”. Or how about: “If you’ve just stolen something from a store, don’t do anything to draw attention to yourself.” That would have been handy advice for Michael.
I will politely say that this may not be true 100% of the time.