SAN MATEO, Calif. — One morning in late May, an 11-year-old armed with a fake mustache had a mission: fool Roblox’s age-estimation tool into thinking he was older. But moments after Cole Moretti looked into the camera, the system flagged him as a child between the ages of 9 and 12. Moretti was one of several children brought in by NBC News to try the technology at Roblox’s headquarters. “Sorry, you can tell your friends at school it doesn’t work,” Eliza Jacobs, Roblox’s vice president of safety