Apple support discussion:
My first thought was how irresponsible it is to rely on a consumer gadget for something life critical. But then I wondered, is there is any such thing as mission critical alarm clock that this person could find and afford? Can the average layperseon be expected to understand how various gadgets are prone to fail at such simple tasks? We rely on so many non-industrial grade things to not incidentally kill us: shoes, doorknobs, bubblegum, faucets, etc. Maybe it's reasonable to think of a virtual alarm clock in the same way, especially on a device that tries so hard to look and feel like an elementary object rather than a complex machine.
In response to the guy behind you: I did some googling for high-reliability alarm clocks, and didn't find anything relevant. Designing one would be amusing, in the standard vein of engineering humor. (Ha ha, isn't this horribly over-designed.) Redundant power supplies! Integral UPS! Three rad-hard microcontrollers which vote on the correct time! Two displays, in case a LED segment on one fails, and gives you the impression of the wrong time! Costs $5000, and weighs 40 pounds!