Glenn Fleishman dives into Check In ↦ At TidBITS, Glenn Fleishman takes a deep dive into one of iOS 17’s best (and most carefully implemented) features, Check In. It’s a feature that could lead to enormous improvements in security for lots of people, so long as they know it exists and how to use it: Life can be dangerous but, for most people, most of the time, only in sporadic, u…