I caught half the story and indeed it did seem that the shield wasn't THAT effective - it certainly wasn't acting as a forcefield on the sharks and they could be seen to be swimming quite comfortably close to the divers without being repelled.
the only times I saw that the sharks actually turned away were when the divers made a sudden movement - which would be normally expected to happen.
the fact that several sharks swam up to the underwater cameraman and actually bumped into him, mouth open, makes me wonder just how much of a deterrent these things are.
and the Shark Shield rep also advising that 'we have actually only conducted one official test' on the unit also seemed quite strange - especially when they showed the 'test' involved which was of a large great white swimming up to a diver who then switches his shark shield on and the shark 'instantly' turns away. the fact that the shark turned away when it got within 10-15 feet of the diver seemed like a natural instinct. this shark wasnt showing any 'aggressive' behaviour or in feeding mode.
as they also said, sharks behaviour would be different in feeding frenzies or while they were agitated and the shield 'wouldnt necessarily' prevent a bite in those situations.
I'd suggest that when the sharks are feeding or being aggressive is the ONLY time you'd be likely to be bitten so, to me, they don't really present a compelling argument.
of course I WANT to believe that theres something out there that is a shark deterrent and offers peace of mind to kayakers,divers etc, but I'm not sure whether this product is it. my 2 cents. 8)