For iPhone 13, you need to 'opt-in' for 120 FPS by adding a key to your app's Info.plist file. This is probably something similar.

Could be related to the new 'Find My' functionality where iPhones report the location of devices from strangers around them [1].

[1]: https://i.blackhat.com/USA-19/Thursday/us-19-Krstic-Behind-T....