A lot of times, a short discussion with suspicious individuals, i.e., law enforcement officers, can relieve their paranoia and get them sort of "on our side" or at least neutral.
So often, police misconduct is due to the fear involved and if we can decrease this, the misconduct diminishes.
You're absolutely right about that msmoto and I do believe majority of incidents could be completely avoided, however I believe there are two folds to this issue. First, photography by itself is not and should not be considered a suspicious act and therefore should not be treated as such in the first place. Second, not all cops are created equal and some cops will assume you guilty until proven otherwise... just look at the pepper spray cop of UC Davis for instance.