So, last week I helped one on my coworkers set up their new iPhone 6s. I'm the tech-guy at work.. We went through the initial steps, including TouchID. After completing setup and bla-bla, I pressed the home-button to get her to unlock her phone but IT ACCEPTED MY FINGERPRINT. What the heck? At first I thought it had to be some residual finger-grease-gunk, resulting in "her print" being read, but I absolutely made sure the home-button was perfectly clean. Still accepted my finger. Her thumb, my index - both were able to unlock the phone. I deleted the fingerprint, she added her print again - this time only her finger unlocked. Bug or freak accident?