I usually keep my phone muted and on vibrate. But sometimes after having it plugged in to charge and I go to access it, the sound has come back on without my touching it.
Another one I will have set an alarm but sometimes I wake before it and I shut it off. But the alarm has still gone off despite my turning it off before the scheduled wake time.
Another one I will have set an alarm but sometimes I wake before it and I shut it off. But the alarm has still gone off despite my turning it off before the scheduled wake time.