“We have to monitor social media and the Internet to see if there are any rallies nearby that pose a specific threat, and we avoid them,” he said, adding that the threats sometimes average 400 per minute. Mr. Zimmerman found himself in a threatening situation in Washington, D.C., when Starbucks employees mistook him for his brother. . . . Someone finally noticed the receipt said Robert instead of George, or R instead of G, and they said ‘Oh, it’s not George Zimmerman‘ and they all calmed down. Someone then said ‘Yeah, but you look like that [expletive], and if you...