captioned my image (from behind) as a poacher arrested by the police (I was there as an anti-pouching volunteer instead). That's legitimate as we were reconstructing an arrest by the police of a poacher. The photographer is never there when the real poacher is really arrested
. That doesn't mean that all this posed pictures aren't legitimate as reportage.
A reportage is a photographic service around a story, a theme, a situation. A portrait is a portrait is a portrait.