I've heard that Tony Randall kept campaigning to have the show's production moved to New York, because he felt it would be much more beneficial for the atmosphere they were trying to capture, but to no avail. But I do know that whenever they did film on the streets in New York, it was always in a candid manner . . . you know that infamous shot of Felix trying to help the little old lady across the street? That wasn't scripted: that old lady and boy scout didn't know they were being filmed, and actually thought he was trying to attack her, which is why she hits him with her purse, and the boy scout also slugs him too.
In many of those exterior shots, if you pay attention, you can see certain people in the crowd are taking notice of what's going on, because they're staring directly into the camera with quizzical looks on their faces.
I remember there was an episode of SANFORD AND SON where Fred runs away to Vegas to avoid another earthquake back home (and Redd Foxx was, coincidentally, performing in Vegas at the time the episode was taped); there are several shots where he's in the casinos, or out on the streets, and you can see so many bystanders and other folks looking directly into the camera with these ridiculous grins on their faces that just scream, 'Look, ma! I'm on TV! I'm walking with Redd Foxx!" There was even a scene where Fred approaches a water fountain, and you can see in the background a security guard keeping people back as they try to approach Redd Foxx for pictures.