Really? It would have that effect? If the control signal, video feed and GPS reception is blocked, a Phantom will surely just drift away with the wind or worst case, fly about erratically (creating more danger than if it had been left alone.)
There's also the legality of something blasting out a whole load of possibly prohibited radio frequencies at unlawful power levels.
Anyone using something like this would probably find themselves in more trouble than the multirotor operator.