1. A method for calendar-based coverage monitoring, the method comprising: receiving a coverage rule defining a plurality of covering entities for performing an activity for a covered entity and at least one period of time during which the plurality of covering entities is to perform the activity; monitoring individual calendars for the plurality of covering entities and detecting a change in one of the calendars; determining whether the change causes the coverage rule to be violated; and in response to determining that the change causes the coverage rule to be violated, generating a notification indicating violation of the coverage rule, wherein at least one of the preceding actions is performed on at least one electronic hardware component.