Nah, that's way more work. When doing these kind of meet-on-the-street videos, they'll just film the interactions up front and then have a secondary team of producers to get the people to sign releases afterwards. It's legal to film people in public, you probably just want their permission before showing their faces on TV to avoid a lawsuit. I'm sure these are all the natural reactions from these people, they were just unlikely to get releases from anyone who was particularly spicy (so they'd have to blur their faces and anything else identifying if they wanted to use those spots).