This is what the docs show:

However, in reality, this is what I get:

My goal here is to try and filter out repeat face detections of the same person within a short amount of time. For example, a person walks by the camera, lingers in front of it, shifting around, and each time their face turns towards the camera, it will fire off a face detection event. Because of the extra processing that takes place each time a detection event is received, it would be a lot more economical to filter out excess events of this kind. I could do that if I had those face characteristics, but not without them.
Any thoughts?