Apple patent involves a parent keeping track of a child via an iPhone/Apple Watch combination — Apple World Today

It involves a satellite device (the smartwatch) that can be associated with a user account of a minor (e.g., child or adolescent) user who doesn’t have a smartphone that can be used as a companion device to the satellite device. The Apple Watch can be configured to be used as a primary device, without reliance upon a paired smartphone. 

Certain info can be synchronized with the satellite device via the association with the family account. During initial configuration, a set of cryptographic keys can be generated to associate the account of the satellite device with the set of accounts in the family. The smartwatch can then access calendars, media, or other data that is shared with user accounts within a family of user accounts.