But even if he rejected an exclusive deal he would still need to spend a fortune on security shielding his bride and guests from the media.
"If he decides not to do a deal with somebody, he still has to somehow protect it and that can be a pain dealing with helicopters buzzing overhead," the insider said.
"He did a good job keeping his engagement quiet but it's a lot of work to do that. He just might decide to give it to Woman's Day, they can give him however much money and he will give it to charity."
An alternative was to hold the ceremony overseas.
Since last year's Rugby World Cup, McCaw has taken charge of his own publicity, releasing important announcements, including his retirement from rugby, reaction to his New Year honour and now the engagement, on his Facebook Page.