[WorldMaker]

2 can be mitigated by squeezing the top two buttons of the phone until it vibrates. Any attempt to go to the emergency contact/power off screen disables Face ID/Touch ID until after the next passcode use. (You don't have to entirely reboot.)

[nordsieck]

That is a fair point.

But sometimes you don't have the time. From what I recall, the police were able to apprehend Ross Ulbricht (of Silk Road fame) before he could log out of his computer.

[bookofjoe]

At least that's what happened in the (excellent) movie https://www.imdb.com/title/tt7937254/