1. A method for auditing video analytics data through review of selective subsets of video frame images, the method comprising: obtaining first motion pixel counts from differences within frame images of a video stream of images within a first region of interest that is defined within a field of view of the images; obtaining second motion pixel counts from differences within frame images of the video stream of images within a second region of interest that is defined within the field of view of the images, wherein the second region of interest is different from the first region of interest; determining an occurrence of a first motion pattern within the first region of interest from the obtained first motion pixel counts within the first region of interest over a sequence of the frame images over a first time period; determining an occurrence of a second motion pattern within the second region of interest from the obtained second motion pixel counts within the second region of interest over a sequence of the frame images over a second time period; and determining an occurrence of a triggering alert event in response to a time gap between the first time period, from the occurrence of the first motion pattern from the obtained first motion pixel count, and the second time period, from the occurrence of the second motion pattern from the obtained second motion pixel count, that is longer than a predefined time interval.