This is interesting, but will it work in practice? It seems that this merely relies on the little bump on the plus side of a battery to differentiate between th

This is interesting, but will it work in practice? It seems that this merely relies on the little bump on the plus side of a battery to differentiate between the positive and negative end. But this would make the clearances very small, so I am not sure it will work in practice with different batteries and people jamming them in and out, etc.