iOS 11, released in October, 2017, adds an Emergency SOS feature, which also gives you a way to disable your TouchID feature. Disabling TouchID could be desired in the event of a mugging or an arrest.
You can access the Emergency SOS feature by pressing the Sleep/Wake button 5 times. When you do this, a window will appear which offers 3 buttons. The Sleep/Wake button is located on the right-hand side of most iPhones. On older iPhones it’s the silver button on the top of the phone.
- Slide a button to turn off the phone
- Slide a button to view MedicalID info
- Slide the button to call 911
A secondary benefit of this Emergency SOS feature is that if you click the Cancel button, then TouchID is disabled. Once you do this then the iPhone can only be unlocked by entering your passcode. This subtle change is pertinent since, my understanding of current precedents is that law enforcement can require you to place your finger on your phone to unlock your phone, but they cannot require you to enter a passcode to unlock a phone. Similarly, in the event of a robbery, perhaps it would be tougher for the assailant to force you to type in a passcode compared to forcibly placing your finger on your phone.