There are few pitfalls of being a newly minted billionaire in Sydney, but a distinct lack of privacy when it comes to buying a beachfront getaway is probably one of them.

Consider the plight of techie Mike Cannon-Brookes, whose tranquil visit to the secluded shores of Pittwater’s Great Mackerel Beach by ferry this month sparked speculation he is the mystery buyer of one of its prized beachfront houses.