Charles Darwin observed “ignorance more frequently begets confidence than does knowledge.” That was certainly true in 1995 when a man named McArthur Wheeler boldly robbed two banks in Pittsburgh without using a disguise. Security camera footage of him was broadcast on the evening news the same day as the robberies, and he was arrested an hour later. Mr. Wheeler was surprised when the police explained how they had used the surveillance tapes to catch him. “But I wore the juice,” he mumbled incredulously. He seemed to believe that rubbing his face with lemon juice would blur his image and make...