How I Spent My Strummer Vacation - S14-E2
Corrected entry: In the beginning, Homer states that he doesn't remember that he was going to be on Taxicab Conversations. By the way Disco Stu was talking, the show was supposed to be a secret from the passengers, so if it's a reality show then they shouldn't have told him.
Correction: Hidden camera shows have to get permission from participants after filming so that the footage can be used on TV. Homer and Disco Stu were most likely told after being recorded.