Maybe it was all just a misunderstanding. The sign at Eden Park on Saturday read "Ritchie for Prime Minister", which is not how the All Black captain spells his name.
Perhaps the punter was simply using the occasion to entreat the director of Lock Stock and Two Smoking Barrels to consider a run for office, or urging one of the family behind the bus line to pursue a life in politics.
John Key, the man most famous in world rugby for plunging into the wrong side of a hand-maul, picked the idea up and ran with it on Monday morning, saying, with half a smile, that he thought McCaw as PM was a jolly good idea.
McCaw ruled it out completely and repeatedly: no thanks, he said, going into politics wasn't for him. Which, naturally, prompted countless politicians and commentators to pontificate at length on the possibility of McCaw going into politics.
McCaw has played several consecutive, brutal games of rugby with a fractured fifth metatarsal, but probably he has never tasted quite the pain of a week of conjecture around his suitability for a profession that he appears to regard with at best wariness and at worst contempt.
On top of which, the incessant wittering about that knighthood. I wouldn't be surprised if the poor fellow receives a breakfast text message from the prime minister every morning. "Richie! Can I interest U in a knighthood 2day? Arise! Arise!"
Still, as long as there's a pause in international rugby ahead of the World Cup, the interim national sport is Find A Career For Richie. Truly, New Zealand hasn't witnessed such a countrywide outburst of benevolence since that time we rallied together and tried to get Prince Harry hitched to a local.
In that spirit, here are a selection of post World Cup possibilities for man who has broken as many records as he has bones, probably the greatest All Black of all time.
Royal Highland Fusiliers member: McCaw's interests outside rugby include gliding, drumming and playing the bagpipes. It kind of feels as though everything is leading inexorably towards a starring role in the Edinburgh Military Tattoo.
Novelty superhero: With the pilot's licence, gliding and bagpipes, he's already got most of the important superhero components. SuperCaw could specialise in roadside assistance, given the speed with which he arrives at the breakdown.
Europe: McCaw says he's unlikely to chase the lucre of playing rugby in Europe. But who would begrudge him a season or two at one of those minted French clubs, letting it go on chocolate croissants and cider? Time permitting he could probably sort out the Greece issue.
Olympian: I'm thinking modern pentathlon or rhythmic gymnastics.
International trade negotiator: Who better to persuade the lily-livered protectionist wonks from Japan and Canada that full and unfettered access for New Zealand dairy is a bloody good idea after all? He could also operate as a kind of global shepherd, dealing with sheep-based issues in wealthy global hot-spots such as Saudi Arabia and Herne Bay.
International peace broker: Peace in the Middle East has suffered another setback with news Murray McCully is to be distracted by a pesky auditor general inquiry into the Saudi sheep farrago. McCaw could use his conciliatory powers to bring Israel and Palestine to a truce; that achieved, a road map to peace between Winston Peters and Mike Hosking.
Criminal: McCaw has proven himself adept at stealing others' possessions. According to Springbok veteran Victor Matfield, authorities "let him get away with murder".
Heat pump advertising: The cricket was good, but the real emotional rollercoaster at the World Cup was the heat pump ads with Fleming and Astle. Just imagine - dare to dream! - what the same film-makers might create with McCaw and Carter.
Auckland mayor: He wouldn't even have to live here to get things moving. "Can I interest you in a knighthood this morning?" "Sure, JK, as long as you give us that dosh for the rail link." "Putting it through now, Richie!"
A new flag for New Zealand: No, not a picture of him on the flag, that would be absurd. Instead, make him the actual flag. How pioneering would that be? New Zealand: the first country to give women the vote, the first country to introduce electronic transactions at retail outlets nationwide, and now the first country to have a living, breathing human being as its official flag.
A new national anthem for New Zealand: He wouldn't be the national anthem. That would be weird. He'd lead the panel to come up with a new anthem. A few weeks ago McCaw said he likes the Survivor track Eye of the Tiger, which would make an excellent anthem, refashioned to take in the Maui myth of fishing up the North Island as "Te Ika a Maui".
A new name for New Zealand: As panel chair, McCaw could persuade Helen Clark to appoint a UN special rapporteur for a reassessment of "New" designations. For example, New York becomes just York, and the pretty old city in northern England becomes Old York. New Zealand would become Zealand, and that coastal chunk of the Netherlands, Old Zeeland.
We could go with the obvious choice of Aotearoa but the problem is that when the Black Caps played in Zimbabwe during Maori Language Week with "Aotearoa" on their shirts, they lost.
A new accent for New Zealand: The killer argument for changing the flag is that it is constantly confused with Australia's. Precisely the same problem pertains to our respective accents. Who can honestly say they haven't been mistaken for an Aussie in a south London ? Sir Richie, draped in our new flag, would be ideally placed to lead a panel to decide on a new accent, so we are no longer difficult to distinguish in global markets. I suggest we start with Steve Hansen's unique drawl and take it from there.
All Black: He hasn't actually said he'll retire. Play all the World Cup games and he'll be on 149 test caps. One more to round it off? What the hell, maybe another four or five years.