Casio makes inscrutable watches. I suppose there's only so much U.I. you can do with 4 buttons. My Casio Illuminator Five Alarms W-213 started alarming at midnight.
In the course of pushing buttons, it is easy to accidentally enable an alarm. (e.g. If you get the digits flashing to set an alarm, it auto-enables the alarm, even if you don't change the time.)
It is much harder to disable the alarm. Here's how:
Human Factors comment: Making the default alarm time for your product be midnight is inconsiderate. Yeah, I know -- you defaulted to zero. That's a very programmer thing to do. But when I accidentally enable an alarm, I really, really do not want it to wake me at midnight.