As reported, last week, by The Verge iOS 11 has a way to quickly and discreetly disable Touch ID.
Apple is adding an easy way to quickly disable Touch ID in iOS 11. A new setting, designed to automate emergency services calls, lets iPhone users tap the power button quickly five times to call 911. This doesn’t automatically dial the emergency services by default, but it brings up the option to and also temporarily disables Touch ID until you enter a passcode. Twitter users discovered the new option in the iOS 11 public beta, and The Verge has verified it works as intended.
This is a handy feature because it allows Touch ID to be disabled in circumstances where someone might be able to force a phone to be unlocked with a fingerprint. With Touch ID disabled in this way, there is no way to physically unlock an iPhone with Touch ID without the device’s passcode.
As a side note. Last week Mashable reported that according to a Virginia judge a cop can force you to unlock your phone with Touch id but not with a passcode.
As pointed out by John Gruber:
Until iOS 11 ships, it’s worth remembering that you’ve always been able to require your iPhone’s passcode to unlock it by powering it off. A freshly powered-on iPhone always requires the passcode to unlock.