Officials in charge of stopping ambush marketing at Eden Park have already thwarted an attempt at a rugby game in the lead-up to the tournament.
A group of young women dressed identically in black were dropped off some way from the stadium for a Blues Super 15 match, but were spotted by Auckland Council staff and stopped by security at a gate.
The group had tickets to sit together in a block and planned to take off their tracksuits to reveal "skimpy clothing" branded with the logo of a rival to an official sponsor, said Carole Todd, the Auckland Council compliance and licensing manager.
"Ambush marketing" is a common ploy at large global sporting events, most memorably at the Soccer World Cup in South Africa where a group of women clad in orange captured the attention of camera operators.
The South African girls were promoting a beer brand which rivalled the official tournament sponsor.
Ms Todd expected any similar attempts at the Rugby World Cup to be smarter than the group of girls the council stopped at Eden Park.
"Perhaps they will send in people separately, or dressed differently rather than wearing matching outfits. We have to be vigilant."
Other ambush-marketing ploys to be watched include merchandise giveaways, such as flags, hats or scarves, to thousands of rugby fans making their way to the ground.
"Or a booze bus turning up and giving away free shots of alcohol from a rival liquor company, for instance," said Ms Todd.
"Anything which might undermine the marketing of the tournament by piggybacking off the event itself.
"Official sponsors don't spend all this money on a tournament for other people to pop in and steal their thunder."
Auckland Council staff will be joined by Ministry of Economic Development investigators to enforce the anti-ambush marketing law, the Major Events Management Act.
Council staff will concentrate on street trading and businesses within "clean zones" around match venues selling products they would not normally sell.
They will also stop any distribution of flyers and pamphlets within clean zones - a 500m radius around stadiums - as well as vehicles marked with branding or advertising parked in the clean zones.
For most of the tournament, the clean zones will be in force on match days and the 24 hours beforehand.
That time-frame will be extended to two days before the quarter-finals and the semifinals, then right through to October 24 - the day after the final.
A ministry spokesman said the vast majority of problems were expected to be "born out of ignorance of the rules, rather than deliberate attempts to flout them".
"We will be working with the council to deal with larger problems, like the ambush-marketing attempts. We'll be looking for the billboard or the banner that springs up trying to cash in."
However, if people involved in ambush-marketing stunts manage to get inside the stadium, the responsibility to minimise the impact on official sponsors falls to Rugby World Cup Ltd, which owns the tournament.
Ross Young, general manager of RWC Ltd, said genuine fans in the crowd wearing clothing with rival branding would not be targeted.
"That's not an issue. We're not going to be jumping up and down like the Gestapo."