Victoria Pendleton will not be able to tweet about tucking into her Weetabix on the morning of race day, or post a video message to fans from her room in the athletes' village.

Pub landlords will be banned from posting signs reading: "Come and watch the London Games from our big screen!"

Fans in the crowd won't be allowed to upload snippets of the day's action to YouTube – or even, potentially, to post their snaps from inside the Olympic Village on Facebook. And a crack team of branding "police", the Games organisers Locog have acknowledged, will be checking every bathroom in every Olympic venue – with the power to remove or tape over manufacturers' logos even on soap dispensers, wash basins and toilets.

With just a little more than three months to go until the opening of the London 2012 Games, attention is increasingly turning to what many legal experts consider to be the most stringent restrictions ever put in place to protect sponsors' brands and broadcasting rights, affecting every athlete, Olympics ticket holder and business in the UK.

Locog insists the protections were essential to secure the contracts that have paid for the Olympics, but some fear the effect could be to limit the economic benefits to the capital's economy – and set a precedent for major national celebrations in future.

Britain already has a range of legal protections for brands and copyright holders, but the Olympic Games demand their own rules. Since the Sydney Games in 2000, the International Olympic Committee (IOC) has required bidding governments to commit to introducing bespoke legislation to offer a further layer of legal sanction.

In 2006, accordingly, parliament passed the London Olympic Games and Paralympic Games Act, which, together with the Olympic Symbol (Protection) Act of 1995, offers a special level of protection to the Games and their sponsors over and above that already promised by existing copyright or contract law. A breach of these acts will not only give rise to a civil grievance, but is a criminal offence.

"It is certainly very tough legislation," says Paul Jordan, a partner and marketing specialist at law firm Bristows, which is advising both official sponsors and non-sponsoring businesses on the new laws. "Every major brand in the world would give their eye teeth to have [a piece of legislation] like this. One can imagine something like a Google or a Microsoft would be delighted to have some very special recognition of their brand in the way that clearly the IOC has."

As well as introducing an additional layer of protection around the word "Olympics", the five-rings symbol and the Games' mottoes, the major change of the legislation is to outlaw unauthorised "association". This bars non-sponsors from employing images or wording that might suggest too close a link with the Games. Expressions likely to be considered a breach of the rules would include any two of the following list: "Games, Two Thousand and Twelve, 2012, Twenty-Twelve".

Using one of those words with London, medals, sponsors, summer, gold, silver or bronze is another likely breach. The two-word rule is not fixed, however: an event called the "Great Exhibition 2012" was threatened with legal action last year under the Act over its use of "2012" (Locog later withdrew its objection).

A photoshoot promoting easyJet's new routes from London Southend airport was also interrupted by a Locog monitor after local athlete Sally Gunnell was handed a union flag to drape over her shoulders. According to reports, Locog felt this would create too direct an association with her famous pose after winning Olympic gold in Barcelona in 1992 (British Airways, rather than easyJet, is the airline sponsor of London 2012).

Locog chose not to comment on the incident, but aspokeswoman said: "If we did not take steps to protect the brand from unauthorised use and ambush marketing, the exclusive rights which our partners have acquired would be undermined. Without the investment of our partners, we simply couldn't stage the Games."

In this climate, according to Chris Moriarty of the Chartered Institute of Marketing, non-sponsoring brands are being forced to seek expensive legal advice on how to stay just the right side of the line.

He cites a campaign by Marks and Spencer, with the slogan On your marks for a summer to remember, which features union flags, an egg and spoon race and an oversized gold medal, neatly dancing around the guidelines. A campaign by Nike called Make it Count, featuring Olympic athletes Mo Farah and Paula Radcliffe has proved an even greater success: a survey of Tweeters found that Nike (a non-sponsor) is the brand they most associated with the Games, instead of Adidas, which paid £100m for official rights.

"Small businesses don't have the resources to have a creative campaign like that, but also, I detect, they are too scared to do anything, because the landscape is so complicated, and there are so many dos and don'ts," says Moriarty. "It would be an awful shame if small businesses were too afraid to gain from the biggest show on earth coming to London."

The CIM has called the restrictions around the London Games too draconian and raised concerns "that a precedent will have been set which unduly prohibits businesses tapping into current national and societal events".

One of the IOC's principal fears in seeking bespoke legislation was around so-called "ambush" marketing, according to Locog, where businesses try to leapfrog or otherwise wriggle around branding rules. At the 2010 World Cup, 36 female Dutch fans were thrown out of a match for wearing orange dresses without logos, in what organisers deemed an ambush campaign by the beer company Bavaria. (Fifa also requires bespoke branding legislation).

Industry experts believe the ambush battleground at the London Games is likely to lie in social media - still relatively new to the Games. "The big opportunity really is going to be in the online space, because there [the law] becomes a little bit more of a grey area, particularly in social media," says Alex Brownsell, news editor of Marketing magazine, "and that's where Locog are anticipating more guerilla marketing. It's harder to police and the legal influence over this kind of area is more hazy."

At the Beijing Games – where internet restrictions were also in place locally – there were around 100 million users of social media worldwide, but the organisers had no social media presence. For London 2012 there will be more than 2 billion, and the IOC, to its credit, is making heroic efforts at engagement.

"We are at a dawn of a new age of sharing and connecting," says Alex Huot, the IOC's Swiss-based head of social media, "and London 2012 will ignite the first conversational Olympic Games."

Can Games organisers police social media chatter? Twitter has already agreed to work with Locog in barring non-sponsors from buying promoted ads with hashtags like #London2012.

The organising committee has also put together a detailed social media and blogging policy for athletes, so that they don't accidentally fall foul of regulations - by Tweeting about a brand that isn't an Olympic sponsor, for example. (During "Games Period" - 18 July to 15 August - advertising rules become much stricter for athletes, banning all non-sponsor endorsements.) Like all attendees at any Olympic venue, there is an absolute bar on athletes uploading snatches of video or audio, which would contravene lucrative broadcasters' rights.

But will Locog really disqualify Usain Bolt if he Tweets about drinking Pepsi? (Coca Cola is the main softdrink sponsor.)

It's inconceivable, says Jordan. "As with many rules and regulations, some of the sanctions are very draconian, and rarely used. I do not believe there would be any great appetite for evoking any of these incredibly tough sanctions, and high-profile disqualifications of athletes — that's the last thing they would want."

"We don't police," says Huot, "but we are working closely with all the platforms to make sure that trademark and IP rights are respected and that we have a mechanism in place in case of infringements." He acknowledges, however, that moderating is a technical challenge.

Organisers have asked athletes to report any ambush activities on a dedicated website, OlympicGamesMonitoring.com. It is not accessible to unauthorised persons.

Locog stresses its approach will be "pragmatic" and "amicable" where possible, but even for ordinary ticket holders, the regulations are draconian if it chooses to assert them.

"On a very literal reading of the terms and conditions, there's certainly an argument that the IOC could run that you wouldn't be able to post pictures to Facebook," says Jordan. "I think what they are trying to avoid is any formal commercial exploitation of those images, but that's not what it says. And for that reason, it would appear that if you or I attended an event, we could only share our photos with our aunties around the kitchen table. Which seems a bizarre consequence."

Pressed for clarification on this point, Locog would only repeat its policy that images "can only be used for private purposes".

In such a controlled environment, says Brownsell, there will always be a danger for marketers that association with an event that is seen as overly commercialised or legalistic may be perceived as a drawback. He cites the example of Visa, which experienced some negative press when it was the only payment option offered when tickets were offered for sale.

Ultimately, however, there is a good reason for the restrictions, Brownsell stresses – as a shortfall in sponsorship would have to be made up from the public purse.

"Maybe Locog hasn't put across strongly enough the argument that these companies are paying for the Olympics, and if they weren't paying for it, we would be paying for it."

Banned during the Games: What the rules say

Athletes don't …

• Blog about your breakfast cereal or energy bar if it's not an official sponsor – in Games Period all endorsement is banned.

• Post video clips from inside the athletes' village to your blog or Youtube. No audio or video content from inside any Olympic venue can be uploaded to any site.

• Tweet "in the role of a journalist". Athletes "must not report on competition or comment on the activities of other participants".

Non-sponsor companies and businesses don't …

• Say: "Supporting our athletes at the 2012 Games!" or "Help us make it a Gold 2012!"

• Use images that suggest an assocation with the London Olympics.

•Offer tickets as part of a promotion.

Crowd members don't …

• Upload a clip of William and Kate tripping up the steps of the Olympic stadium to Youtube: "A Ticket Holder may not license, broadcast or publish video and/or sound recordings, including on social networking websites and the internet."

• Post your pictures to Facebook – this may fall under the same restriction.

• Take part in an ambush marketing stunt, "including, for the avoidance of doubt individual or group ambush marketing".