Under Maritime Law, the client would forfeit her right to the salvage if she refused to render aid to a ship/persons in distress.
Great whites are lone hunters. Also, no great white would continue to circle a buoy with no evidence of prey. 3rd, sharks do not make emotional decisions. They can't be "mad" someone hit them in the ampullae of Lorenzini.
The Danish text on the buoy includes the word "not" twice in a row, while missing a functional verb, revealing it was likely not written by an actual Danish person. The first "ikke" should have been the verb "må" (may) and it would actually make sense (as far as grammar goes - still makes no sense to put in on a buoy in the middle of the Pacific Ocean)