Minor Description
It would be good to have a way to supress alerts for a device based on time, not just "until date".
For example, do not alert for device foo between 8pm and 7am every Tuesday (through to Wednesday morning).
Having multiple schedules for a device would be useful too (maintenance windows might be Tuesday and Thursday evenings, for example).
Possibly this could also be applicable to device groups, to avoid configuring the same thing for multiple devices.