The asking price was beyond that of Major and Gardner but they worked out if 5000 Kiwis gave $400 each, or if one million Kiwis gave $2 each, they would have a shot at putting in a successful tender.
And if successful, they would gift the land to the Department of Conservation and the beach would stay in New Zealand hands forever.
Unlike most bright ideas that pop up on Christmas Day only to disappear in the cold harsh light of day with the empties, the notion was still with the brothers-in-law the next day so they established a Givealittle page and went on a charm offensive, asking their fellow Kiwis to crowdfund a beach. The story was picked up by the media and the pledges started coming in.
Midway through last week, the donations began to stall and Gardner and Major began to despair of reaching their goal.
And then along came Gareth Morgan. Morgan has an innate and unerring ability to really, really piss off New Zealanders. Lots and lots of New Zealanders.
There is much that is good about the economist turned philanthropist - good family man, generous benefactor of various causes and charities, a man who is passionate about New Zealand.
And it's hard to argue with much of his reasoning.
Gareth Morgan has an innate and unerring ability to really, really piss off New Zealanders.
Feral cats lead miserable lives and, in turn, go about making the lives of birds miserable.
Morgan has argued that cats should be microchipped or collared - any cat found roaming without identification should be treated as feral and rehomed or put down.
He also wants people to rethink having cats as pets. The reaction was immediate and as feral as the cats Morgan was trying to get rid of.
The response was just as negative when Morgan co-authored a book on the unhealthy diets of New Zealanders.
It had many good points - how to spot "fake" food, what you should eat to live longer - but people took umbrage at being called lazy, fat pigs and at the hectoring tone.
New Zealanders don't like being told what to do, especially by someone they perceive to be privileged.
If you work a 60-hour week and no decent restaurant is open and you're too knackered to prepare a healthy stir fry, you're going to eat a pie, no matter what a multi-millionaire thinks you should do.
So when Morgan announced he was willing to stump up the $600,000 needed to reach the $2m target in return for having private use of part of the beach, there was an immediate, negative response.
Donors threatened to withdraw and Major and Gardner had to move quickly to reassure the public.
They said although his offer may have had the best intentions, his desire to have exclusive access to part of the property contradicted the foundation of the campaign.
In a way, Morgan's ill-advised intervention may have provided the fillip the campaign needed. People who had yet to pledge did so immediately to prevent Morgan having anything to do with the beach.
The $2m was reached on Friday. Whether the tender bid is successful is another matter. The owner of the beach, who's being sued by the BNZ for unpaid loans, clearly needs every cent he can muster and will have to go with the highest bidder.
But the campaign has been a wonderful example of the Kiwi can-do attitude. For those of us who donated, being a part of this crazy notion is as Kiwi as the pristine beach itself.
• Kerre McIvor is on Newstalk ZB, weekdays, noon-4pm