My student didn't turn up for lessons recently. It's a group session so the lessons went on as usual for the rest. A while later, he texted me, apologised and said that his alarm didn't ring and that's the first time in his life that it happened.
It happened for me as well. Usually about once a year, I'll have screw-ups in my gadgets. I usually set alarms in my phone to wake me up in the morning. Two, in fact, and they are all on snooze. In the past, I like to switch off my phone entirely. Some models allow the alarm function to wake up the phone and automatically switch the phone on by itself so that the alarm can ring (not all models though). So, what happened was that my phone didn't wake up and I couldn't wake for my morning lessons.
It really didn't matter how ......