Do I Need Release From People Filmed in Public Place?

Dear Rich: My employer is a an M.D. in Florida, and is getting ready to begin filming for his first documentary. I will be his production assistant, but have very little experience with documentary filming. It is my job to make sure that we have all of our ducks in a row, legally. We are filming patients in multiple locations, so my question is this; Do we need to get a signed release from every person who happens to be in the background when we are filming in public? For instance, we are going to be filming at a local farmer’s market and at a grocery store. I will e handing out releases to anyone we will be directly filming, but if there will obviously be other customers present who may end up in our frame. Do I need to hunt each of them down and get a signed release or else be forced to blur their faces? No need to hunt down bystanders who appear in public places in the background of your documentary. According to our favorite resource on the subject -  Clearance & Copyright: Everything You Need to Know for Film and Television -- there is no general right to privacy for someone who is in a public place. You should obtain releases from your interview subjects, however, and we provide a sample release form and explanation in this entry.