Video camera attached to back of fence

[jodibuck]

High School softball:
The pitcher's father attached his video camera on the fence behind the catcher. The camera itself was located on the back of the fence, and not inside the field of play. The umpire required the camera to be removed. His assigner told him that was the correct procedure. He stated that if the camera was on a tripod behind the fence, it would be legal, but no camera may be attached to the backstop (fence).

I found this interpretation from the NFHS: SITUATION 5: The home coach has placed a wireless camera in the stands behind the dugout which transmits its recording to a monitor in the dugout. RULING: This is legal. Video monitoring or replay equipment must be placed in the dugout, stands or another dead-ball area. (3-3-1, 1-2-8)

The camera was located outside the playing area, attached to the fence. Why would this not be considered a "dead ball area"?