Afterwards, he sent a message on Twitter which read: "In regards to my jersey during the game I'll clarify the situation during the week."
One of the most famous conscientious objectors of all in New Zealand rugby was former Blues and All Blacks loose forward Michael Jones, a man recognised as a great but who refused to play on Sundays due to his religious beliefs.
Williams has surprised virtually everyone with his stance, but Blues skipper James Parsons, who described him in an interview with RadioLive as a "true professional", said he didn't have an issue with it.
"I didn't really notice it during the game and I didn't notice it afterwards," Parsons said. "I don't know the ins and outs. I think it's a personal decision. I think the Blues are handling it by talking to Sonny and his manager directly."
Asked about objection clause in the players' collective contracts, Parsons said he was well aware of it, citing the KFC example without going into details.
"There have been some in the past when some fast food chains have come on board and supported Super Rugby that some players have opted not to be a part of the advertising campaign, but from a personal point of view, as many sponsors as we can get is for the betterment for the game," he said. "From my point of view I just jump on board and try to get behind them if they're prepared to support me."
When asked about the attitude of Williams, who has played 33 tests and has been involved in two World Cup victories with the All Blacks, Parsons replied: "He's fantastic, he's a true professional. He's had great success not only in rugby but in league and you don't get that by being unprofessional, I can assure you of that.
"I'm right behind him as a teammate. That [Williams' stand] is a personal choice and I'll support him with it."