A few months back, a woman’s next-door neighbor, Karen, decided to start teaching yoga classes in her backyard. At first, it seemed harmless enough—just a few mats by the fence. But soon, the “backyard” yoga sessions started creeping over into her neighbor’s lawn. Before long, Karen’s entire group of yogis was taking over half of her neighbor’s yard every Saturday morning. When the neighbor politely asked Karen to keep her classes to her own side, Karen just laughed, saying, “It’s all one big...