No, its not a wasted topic. The glitch people normaly get is when the cage gets destroyed and the mini-mob gets left behind, but if you look at the picture the cages are empty. So are the pigs moving? And if they are what are they doing?
They are orbiting the cage, when you get closer to the mob spawner, they get closer to the centre of the block, when you get farther, the orbit farther away from the centre. It has been talked about in the Giants! thread, but I think that this does deserve it's own thread, so I contribute!