1. There is a difference between an artistic film and a news clip/youtube home video.
2. We've established that this is an artistic film and not a news clip - it's at Sundance, etc. This is also a professional effort - the filmmaker used SAG actors.
3. All people who appear on camera in artistic films are considered performers whether they are starring, have one line, or are in the background.
4. It is a requirement to inform ALL who appear in artistic films that they will be on camera, whether they have one line or 100. This is always done by filmmakers on every level.
5. Not doing #4 is a breach of ethics. You don't get to put people in your artistic film without their consent. If you do, they have every right to sue you and block distribution of your film.
6. It is also considered customary and ethical to pay performers in artistic films - both stars and background. If they are not getting paid, they still KNOW about the film and have consented to be a part of it.