I heard of this scheme as well. My first thought was that at least the someone has self defense in mind. Empowering people and teaching them to refuse to be victims could be only the first step. Towards what I'm not sure. I imagine twenty or so soup cans being hurled at an attacker would have a distracting effect. There would also be the possibility of slipping on the cans once they were all over the floor. In the end though we can all guess what happens when you bring a can to a gun fight.

As a side note, I participated in a defensive pistol scenario that began by throwing a bottle at the nearest popper before drawing your pistol and engaging other targets.