Just press and hold the buttons on both sides. Remember that. Try it now. Don’t just memorize it, internalize it, so that you’ll be able to do it without much thought while under duress, like if you’re confronted by a police officer. Remember to do this every time you’re separated from your phone, like when going through the magnetometer at any security checkpoint, especially airports. As soon as you see a metal detector ahead of you, you should think, “Hard-lock my iPhone”.

John Gruber

Man kann das gar nicht oft genug erwähnen.