To be effective, to involve those later who observe your images, you must get close to your subjects. Shooting safe from a distance or with a mirror to fool them, also makes you distant and uninvolved. But worse, the sneaking with your camera separates you from those you are documenting, and creates suspicion and to them a threat.
I have found getting close, often in their face, gets a more true image of this time and place. But this is important, bring a smile and your positivity. Never cast them in a negative way.
Riots, or civil disturbances are the exception, for which I have chosen to not cover anyway.
Remember what you photograph today has greater importance as time goes by. Whenever possible I try to give a copy to them. Back in the film days there might have been a considerable delay in shooting, and delivery, but I did manage to give quite a few to them. Sometimes this wasn't possible. In today's world I try to email these images back with a note of thanks and