I can see this is a very good idea for those whom don't have strict schedules. Such as working overtime at a job when you normally set through alarmed to turn off silent mode at a specified time which was defined as your normal time but not your overtime which just happened to occur on that day.

In some ways I would prefer this to be somehow integrated into alarmed as part of a GPS event at a certain location. This can thereby minimise the amount of servers (or basically daemons) that needs to be running in the background.

Then again if Shapeshifter (alarmed developer) isn't keen on integration I suppose portions of his idea can probably be copied (after obtaining appropriate permissions of course) for adaptations of his work.

I am not a programmer so I cannot help much I'm afraid. I can definitely see the benefits and if it was integrated into alarmed it would be ideal as alarmed already has plenty of built-in functions that could potentially benefit if one uses GPS rather than setting specified times and hoping that everything would fall into place.