My recollection (and I'm old but not that old) is there was nonetheless a lot of uneasiness by the viewing public as to whether watching, regardless of whether the person later signed a release, was in itself a bit of guilty voyeurism. That the whole concept of the show was in poor taste— catching people off guard and vulnerable.

EDIT: and because I can't not share, this funny clip of Woody Allen on the show: https://youtu.be/LGb_jzaUWOg

Yes, but only because the footage was being used commercially for broadcast. Depending on who was doing the filming they may also have been required to pay the subject; For example, a person who accidentally entered an active shoot of a Hollywood movie encountered the actors and had a short conversation with them. The footage turned out to work well with the scene, and the director wanted to keep it. In order to do so, not only did they have to pay this person and give them credit for a speaking role, they had to be given membership in the Screen Actors' Guild.