The recent rise in flash mob retail thefts and violent crime has hit home on North Michigan Avenue and at other iconic Chicago destinations, deterring holiday shopping and tourism as the city tries to emerge from nearly two years of pandemic stasis. From retailers and restaurants to hotels, businesses are beefing up security and seeking help from law enforcement as visitors stay away in droves, alarmed by the confluence of organized crime and seemingly random assaults plaguing even once “safe” locales like the Magnificent Mile. “People are paying attention to this,” said Kimberly Bares, president and CEO of the Magnificent...