In addition to the horns that plagued the 2010 South African World Cup, fireworks, food, megaphones, hooters, and banners larger than 32 square feet are also prohibited. This is part of the "Stadium Code of Conduct" designed to ensure spectator safety during the event.
The fans are not the only ones facing restrictions. Russia's coach Fabio Capello banned players from using Twitter during the games.
"I don't like it when people are constantly scribbling and publishing something on Twitter. So Twitter is completely banned. But text messages are still allowed," Capello told the Russian press.
The Argentinian team may face FIFA sanctions after they held up a banner saying "Las Malvinas son Argentinas" (the Falklands are ours) before their match with Slovenia. FIFA said their lawyers are reviewing the situation, but others said they clearly broke the organization's rules on making political statements.
The 2014 World Cup will begin Thursday with the first game between Brazil and Croatia.