Some phones have a duress button, e.g. pressing the power button rapidly five times will lock the device and disable less secure methods of unlocking it such as fingerprints and face unlock.
Another example would be using a reset button to wipe encryption keys from memory or hide what you were doing with the device at that moment.
Say you did this when you had reason to think you might be arrested, or after being arrested, would it be a crime? Is changing the state of something in this way destruction of evidence, for example?