I have to wonder how much is deference to the dogs' pack order with respect to the cats. We've had both situations, and only when the cat had superior standing would something like that happen. When the dogs dominated, it was usually the other way around. Most owners don't/won't tolerate the dog having dominance, so the dog won't act aggressively/dominantly toward the cat while the alpha (behind the camera) is present. Things may or may not be different in a situation without a human present, depending on which critter ranks higher in the dog's view.

We've seen it both ways.

Doc