Some of the above discussion reminds me of a group of my fellow street singers (buskers) in New Orleans back in the late 60s/early 70s.

Three very aged Black gospel singers (2 women & 1 man) who used to work the French Quarter were filmed and recorded for the movie Easy Rider. The visual image of them performing on the street appears only very briefly, but their singing continues for quite a bit longer and provides a very haunting soundtrack for the entire climactic Mardi Gras cemetery/acid-trip scene.

These very simple folk were accustomed to getting by on a very modest income, and (as old as they were) probably had no idea of the magnitude of resources available to a Hollywood filmmaking company. I have often wondered if they received appropriate payment; it would have been very easy to deceive them and buy them off very cheaply. My best guess is that they got a flat one-day payment as "extras" but no additional consideration for their sizeable and critical contribution to the musical setting of the film.

Incidentally, that film had already been produced, and I had already seen it, by the time I first arrived in New Orleans. When I first met the little gospel group, I did not immediately recognize them from the movie, and we never talked about it. It was only later, when I saw the film a second time, that I recognized my friends ~ who by that time had disappeared from the streets, probably gone off to nursing homes by that time if not to their eternal rewards.