Lawyers always give this advice, because by the time a case gets to a defense attorney, the defendant's statements to police can only be a negative. But in the case of a minor traffic stop, you can often avoid a ticket by being polite and apologizing. Or, stated conversely, you can turn a planned warning into a ticket by being a jerk or totally non-cooperative. (Caveat: I am a white dude. This may not work for all races and genders.)