My wife, Kayla, and I bought our daughter Rosalind her first phone when she was 12 years old. It came with the usual rules and warnings. We had to know her password; there would be controls on what websites she could use. She could never meet in person anyone she got to know in a chat room, and as parents, we could check her phone whenever we liked for inappropriate content. For the first few months, Kayla checked the pho...