Yeah, I do, and you wouldn't believe it, but doing so cost me a tour around the Grand Canyon. I was traveling through the US at the end of 2010/early 2011 and was in Vegas for NYE, which was when the alarm clock glitch hit. We'd been out on NYE, of course, so didn't set an alarm for January 1, but the next day we had a tour booked for the Grand Canyon- we had no idea about the alarm glitch, and it bizarrely affected January the 2nd too. We slept in past the tour bus pickup and missed the tour, which was non-refundable.
I've since learnt to set a second, separate, alarm for important events.