In Command 100, Register 10, Bit 'C' controls Automatic Wakeup...
a value of '0' will disable Automatic Wakeup,
a value of '1' will Enable with Wake-up Tone,
a value of '2' will enable with music, and
a value of '3' will enable with intercept to RAD.
Another possibility to check: If the property has voice mail, and if the voice mail offers the guest the option to set their own wakeup call, and if the voicemail isn't integrated with the PMS to reset the boxes for new checkins... could be a wakeup was set by a guest with busy fingers and has never been canceled. I know that's reaching a little but I've seen weirder stuff happen.
And the default code for CFBNA is '60'
