While he was away it seems the tax officials went to play with their half-baked monetary schemes.
No sooner had the Prime Minister fluffed up his hair after his sombrero-wearing days in South America when he had to contend with the results of his minx of a Revenue Minister, Peter Dunne, allowing his officials to don their thinking caps.
While in South America, Key had widely trumpeted the virtues of doing business in New Zealand, virtues which included a simple tax system. He returned only to find those officials had got bored and come up with all manner of pick and mix new taxes, taxes on carparks, on laptops, on smartphones.
Dunne sought to dampen the outrage by pledging not to make any changes unless a consultation process threw up "anomalies or inconsistencies that need to be resolved in the interests of fairness and equity".
He did not know that just five minutes earlier, the Prime Minister had been "consulted" and unilaterally thrown the idea out of the water.
It was an occasion in which those two certainties in life - death and taxes - collided.
The happy result was the death of taxes, overwhelmed by the even more potent force of politics. The basis for the Prime Minister's decision appeared to be because of the anomalies and inconsistencies such petty taxes would create in National's polling numbers.
While the big picture issues such as asset sales might have washed off the populace's back like water from the proverbial duck, little petty irritants can hobble a Government's poll ratings quicker than unwise investments can hobble a coal company's bottom line.
During their short life, the proposals nonetheless had some entertaining side effects. In his reshuffle, Shearer gave Cunliffe the revenue portfolio. It is usually a sleepy little technical dell in the landscape of politics.
So how annoying it must have been for such a political football to pop up for Cunliffe to kick around just a month later. Nor did Cunliffe waste his opportunity.
His mug was all over the place. In the end, it was the Prime Minister who did Shearer an unintended favour, cutting off Cunliffe's oxygen supply by ruling out the taxes, meaning that by yesterday Cunliffe was back in the box that in his glory days as a minister he had suggested others inhabit, and wittering on about the long-finned eel.
That was not the only madness that awaited the Prime Minister. While Labour's Grant Robertson and Trevor Mallard derided Key on Twitter respectively as an "embarrassing uncle goes global" and "village idiot on tour" for his sombrero-wearing efforts overseas, it soon transpired that their own leader had an embarrassing bank account overseas. Shearer hoped for some clemency by dobbing himself in for his "oversight" in failing to declare the New York Chase bank account in the Register of Pecuniary Interests for four years running.
A bank account is not quite as sinister as shares in a company that the politician may or may not have spoken out on publicly, or whopping great donations that only became known when the donor has a fit of pique a few years down the track.
But it did seem a bit off for the leader of the so-called working class party to forget he had more than $50,000 sloshing around in his New York bank account when it came to declaring his financial interests.
Shearer's revelation certainly tickled Act leader John Banks' cockscomb. The effect was as if Banks had bathed in the spring at Lourdes and drunk from the Zamzam Well.
His memory was miraculously restored. Having forgotten about donations to his Auckland mayoral campaign by SkyCity and Kim Dotcom, and confused helicopter rides to Dotcom's mansion with cabbage boat rides down the river, he could suddenly recall word-perfect everything Shearer had said about Banks' own past lack of memory. It is hard to begrudge him the joy of his rare opportunity of crowing from the higher moral ground, albeit still at sea level. He had two long days of fun.
On the first, he demanded Shearer follow his own advice and stand down for serious memory failure.
On the second, he scoffed at Shearer's lack of financial competence, wondering how a man who hoped to lead the country could simply let his savings wallow away in a US bank account at a time of low interest rates and a diabolical exchange rate, while he had a mortgage bubbling away on at least one of his three properties back in New Zealand.
As for Dunne, he also had a convenient memory surge. Under attack from Labour over his taxes, he recalled a time when Labour had also proposed a tax which just as swiftly disappeared: that tax was a capital gains tax on overseas bank accounts. It was not enough to save him.
That famous cowlick was flattened by the dunce's cap the Prime Minister had brought him back as a souvenir.