Personally from my Samsung phone - it had enabled gestures by default. This allowed you to tap the screen a few times and it would present you with the lock scr

Personally from my Samsung phone - it had enabled gestures by default. This allowed you to tap the screen a few times and it would present you with the lock screen which has the emergency call button. From personal experience - the phone will wake up and go into this menu if you sweat and have the phone in your pocket.