Open carry is unrestricted at the NRA annual meeting in Louisville, Ky, this year. But with presidential candidate Donald Trump speaking at the Leadership Forum, the Secret Service set up a system to stop the entrance of people with guns and knives. Doug Ritter of Knife Rights realized that the carry of pocket knives is common with people across the United States, and that it is a major inconvenience to trudge a half mile back to a parked car to deposit a pocket knife after walking through a quarter mile line to hear the speakers.The procedure was simple. Hand...