I SPENT the summer producing new “Candid Camera” shows, and among the many things I observed after a 10-year hiatus was that people are more easily fooled than ever. That may seem counterintuitive, but I’m certain it’s true. Much has to do with multitasking. When my dad, Allen Funt, introduced the show over six decades ago, he had to work at distracting people. Nowadays they do it to themselves. Many people we now encounter are fiddling with cellphones and other devices, tackling routine activities with less-than-full focus. That makes them easier targets for our little experiments, but also more vulnerable...