There is also the chance that the victim's were actors who played along. But nonetheless it was all entertaining and shows how people can or do get scammed. Whether the taping was actually real is not as important as the information exhibited.
That is always a possibility with TV magic but then the actors need to get a full paycheck for a two hour show. Question is, do you pony up the money for a full time actor(as big a role in the episode as Paul's) and risk a possibly recognizable face (many guest actors make the rounds on TV shows and commercials)? Or do you take the chance that you will have to re-shoot the entire scam all over again with another person who perhaps is more willing to be seen on TV? Honestly six of one, have dozen of the other.