`setVisible` just hide the object from rendering, but the logic and physic are still active,
* http://www.blender.org/documentation/blender_python_api_2_67_release/bge.types.KX_GameObject.html#bge.types.KX_GameObject.visible
we might want to `suspendDynamics` as well ?
* http://www.blender.org/documentation/blender_python_api_2_67_release/bge.types.KX_GameObject.html#bge.types.KX_GameObject.suspendDynamics