I wasn't all that young when I believed this.
A few years back, there was a reality show called Murder in Small Town X. One of the contestants was the "murderer", and the object of the game was to figure it out. The contestants were eliminated by being "murdered".
I wondered why anyone would sign up for that show if they were going to die.
A childhood belief about people

others believed things like this
- I used to believe the show Law and Order was a gardening show called Lawn and Order.— Adriana
- I thought that every TV show was filed live, and I always wondered why they never messed up.— Steve
- I used to believe my dad was the best male figure in the world and wondered why he wasn't president already.— Ivy :)
- I used to think that 'black comedy' was show like Family Matters and The Cosby Show.— Katie
- I used to think that every time a show came on tv, that the actors were inside my tv acting out the show.Anon
- I used to believe that there was an actual show, listed in the various guides, called "To Be Announced."— Donna