According to legend, British conductor Sir Thomas Beecham once saw a distinguished-looking woman in a hotel foyer. Believing he knew her but unable to remember her name, he paused to talk with her. As the two chatted, he vaguely recollected that she had a brother. Hoping for a clue, he asked how her brother was doing and whether he was still working at the same job. “Oh, he’s very well,” she said, “And still king.”

A case of mistaken identity can be embarrassing, as it was for Sir Beecham. But at other times it may be more serious, as it was…