Very true - there have been times when I've woken up hours late and found my alarm deactivated, with absolutely no recollection of turning it off. The things one can do while asleep are amazing..!
I have accidentally managed to train myself to get up, cross the room, turn my alarm off and go back to sleep... all without any conscious thought. It's not very helpful.
In high school, I asked my mother one night to wake me when a meteor shower was happening. In the morning, I was angry at her, because she didn't wake me. She informed me that not only did she wake me and we saw the meteor shower, we had a full conversation about the meteor shower before I went back to bed.
In college, I once climbed out of my loft, walked over to my desk, turned off my alarm, climbed back into bed, went back to sleep, and didn't remember doing so when I woke up.
