She is a student. Between class and a part-time job, she stops at the campus library to print out a research paper. She enters the building and a security guy watches as she is fumbling through her bag in search of her student ID. After a while, she comes to the conclusion – she left it on her desk this morning. She is rushing back to her dorm to grab it, but can’t get into the building without her ID card. Before she can call her roommate for help, the alarm rings on her mobile phone. It’s morning. Everything is fine. She has her digital student ID card in her mobile wallet and always on hand.