On top of this, iOS 11 introduced an emergency mode that is enabled by tapping the standby button five times rapidly. It is easy to do discretely in your pocket, and it locks your phone by requiring your passcode to be entered again.
Your phone can be easily restored from an iCloud backup once you've got access to wifi. You can always restore from another device or backup if there's data you don't want seen if somehow you can be compelled to do a restore.
From macdailynews:
"iTunes backups are still there for iOS devices, but performing a restore won’t transfer your apps from your Mac, but will instead download them over the Internet from Apple, which is, of course, likely to be slower."
My Android forces PIN entry after 5 wrong fingerprints.
So if you chose only 1 finger and you chose it randomly, they will have a 50% chance of getting in after 5 attempts.