Johannesburg ? More than 30 women showed up at the Netherlands-Denmark match wearing orange mini-dresses emblazoned with the name of a Dutch brewery — earning them a red card from World Cup officials who acted to quash what they called an ambush marketing scam.

Barbara Castelein, left, and Mirte, both from the Netherlands, walk Tuesday outside the Soccer City stadium in Johannesburg. FIFA questioned more than 30 women who showed up for a World Cup match in orange mini-dresses that are the symbol of a Dutch beer advertising campaign.

The stunt may have irked FIFA, soccer’s governing body. But it got Dutch brewer Bavaria NV what it wanted.

“That’s the free publicity they were looking for,” said John Sweeney, head of advertising at the University of North Carolina’s school of journalism and mass communications. “But (for FIFA), there’s paranoia about ambush marketing. Sponsors pay a lot of money, and are demanding exclusivity.”

Companies such as Budweiser pay millions to have their names attached to the World Cup, and FIFA has plenty of incentive to protect its sponsors — almost $300 million. According to FIFA’s 2009 financial report, 97 percent of the federation’s $1.06 billion in revenues came from TV and marketing rights, with sponsorship deals providing $277 million.

But the sponsorships don’t pack the same punch if two or three companies can claim to be the “official (fill-in-the-blank) provider of the World Cup,” which is why FIFA goes to great lengths to protect their exclusivity. Only official partners may use the World Cup for advertising and promotion campaigns.

In ambush marketing, non-sponsors try to sneak their logos or associate their brand names with a major sports event to reap free advertising. Imagine a pack of Bud Girls showing up at an event where Miller was the official beer sponsor.

So organizers of events like the Olympics or the World Cup employ staff to make sure that non-sponsors or their logos are kept out of sporting venues.

When Bavaria’s orange mini-dress brigade showed up at Monday’s game, FIFA was ready. Budweiser is the official World Cup beer, the only one sold at World Cup stadiums and official fan viewing sites. Anheuser-Busch Inbev is one of FIFA’s eight “second-tier” World Cup sponsors, giving it exclusive sales rights.

Bavaria NV has been selling special eight-packs of beer including the skimpy orange “Dutchy Dress” since April. Bavaria’s name is on a small blue tag at the bottom of the dress.

Barbara Castelein and a woman who would only give her name as Mirte said Bavaria NV gave them an all-expenses-paid trip to South Africa. They and 34 women who live in South Africa went to the Netherlands-Denmark game dressed as Danish supporters. But in the 25th minute of the match, the women stripped off their red-and-white gear to reveal their bright orange dresses, tossing the other clothes into the crowd.

FIFA officials escorted the women out of the stadium after the game and took them to the nearby offices of the South African Football Federation, where the women said they were questioned for several hours. “There were no arrests. No one was detained,” FIFA spokesman Nicolas Maingot said. “The only thing that we have done is actually asking some details (from) these women who have been involved. What seems to have happened is that there was a clear ambush marketing activity by a Dutch brewery company.”

Bavaria NV did not return several phone calls seeking comment Tuesday.