Hi Sheldon,

  First off my apologies for replying late. Consider this, if you have configured your alerting to not to send alerts via sms/voice and email for a particular time window then you will not be able to receive you any alerts if something goes wrong in your environment. I am not sure if this will be a good option then. The reason for email being mandatory is this.

I will leave this to be discussed here, so that other community members can comment here on what they feel about this request. 

-Jasper

Product Manager, Site24x7