Not what you're looking for, but it's worth knowing that since iOS 11, there is a panic sequence that disables TouchID at least. This applicable in non-border LE interactions where a citizen can be compelled to touch the device, but not to give up their passcode (IANAL, this might be out of date, as precedents change).

https://www.macrumors.com/how-to/emergency-sos-iphone-ios-11...