Those questions are academic now because no one got bitten. But whether that was the SharkPODs' work or not is anyone's guess. Using highly sensitive pores in their snouts, sharks detect electrical impulses in the water that lead them to food. For instance, some sharks can detect the heartbeat of a seal 60 feet away. By transmitting certain unappetizing electrical impulses, it's a bit like creating a haze of smelly cigarette smoke around a diver.
Experts concur the SharkPOD concept has merit, but say it's hard to ascertain how effective it is.
For their part, SharkPOD developers say they have plenty of anecdotal evidence but acknowledge residual uncertainty always will remain. He's tested it in some cases by attracting great white sharks with food, and then switching the unit on as they approach. They've turned and flicked away. The unit is designed to be switched on as soon as a user enters the water, and remain on until he or she leaves. That's because any shark already aroused into feeding behavior may be harder to dissuade than one just cruising around looking for an opportunistic lunch.