1. A method for processing events generated from an evaluation of a stream of video frames, the method comprising: obtaining characteristic values for an observed event in a scene depicted by the stream of video frames; updating a learned state of the scene based on the characteristic values, wherein the learned state provides a model of patterns of behavior generated from evaluating a plurality of foreground objects detected in the stream of video frames; parsing a list of alert directives for a matching alert directive having ranges of criteria values, wherein the characteristic values are within the ranges of the criteria values and wherein the alert directive overrides a decision to either publish an alert or to not publish an alert for the observed event based on the updated learned state of the scene without changing the updated learned state of the scene; and upon identifying the matching alert directive, either publishing the alert or not publishing the alert according to alert directive.