Businesses looking to the World Cup to boost profits should be aware of breaking copyright laws, legal experts and business groups have warned.
The list of the sorts of activities that could get businesses into trouble is a long one.
Phrases "South Africa 2010", "Fifa World Cup" and even images of the trophy itself are protected under intellectual property laws.
Fifa has had reports of thousands of rule breaches.
The UK's Federation of Small Businesses (FSB) said UK firms should be wary.
Businesses are keen to use the World Cup to drum up extra sales, especially those in the hospitality trade such as pubs, bars and cafes.
But Fifa's stance underlines the vast web of business interests that have grown up around global sporting events and created a legal minefield for those not on the official sponsors list.
Clive Halperin, an intellectual property expert at law firm GSC, says: "Using an image of the World Cup trophy, the three lions logo or even the word Fifa could lead business into trouble.
"Sponsors pay huge money for the right to link to the World Cup, they won't pay that money unless they believe Fifa will vigorously protect their interests."
The FSB's spokesman, Stephen Alambritis, has one key piece of advice - do not use logos. Aside from the three lions, the most obvious one to avoid is Fifa's official emblem of the tournament - the kicking man logo.
But even words should be used with care, says Mr Halperin. "I was walking to work and passed a pub promoting itself with the words 'Fifa 2010 World Cup - watch it here'."
He thinks, technically, that the sign could be in breach of the law, if it was used along with a brand image that was not an official sponsor.
These phrases, which are trade marked, can be used for what is called "legitimate descriptive purposes", such as telling potential customers that a match is being played at a certain time.
However, no companies or brands should be directly linked to the phrases if they are not an official sponsor of the tournament.
What is less of a grey area is using the image of the cup itself. Printing off an image of the World Cup trophy for business use will put you in technical breach of both trademark law and copyright.
Unlike trade mark law, copyright law provides no defence for "legitimate descriptive commercial use".
Fifa's lawyers have already dealt with thousands of cases worldwide - although experience from the previous World Cup in 2006 suggests the vast majority of these are resolved after Fifa sends a warning letter.
Phil McCabe, from the Forum of Private Business, says World Cup legal issues are not at the forefront of his members' minds.
He does, however, urge members to take care. "Certainly, pubs screening games or businesses producing merchandise during the tournament should avoid using trademarked logos such as club emblems or Fifa and FA logos."
Fifa publishes a Public Information Sheet on its website, which outlines what it considers to be its rights and, importantly, gives examples of some dos and don'ts.