By Mark Gregory
BBC World Service business reporter
In South Africa there is controversy over commercial sponsorship rules that have led to the confiscation from fans of food and beverage products during the Cricket World Cup.
Important decisions have been taken off the pitch too
Four companies, including the drinks giant Pepsi, have paid millions of dollars to be nominated as the tournament's official sponsors.
In some cases cricket supporters have not been allowed to take the products of rival brands into matches.
This is because big firms have paid vast sums to sponsor major sports events in the past, only to find that rivals have reaped most of the marketing benefits by staging stunts that have drawn attention to competing brands.
This practice is known as ambush marketing.
The South African authorities have gone to extreme lengths to make sure this does not happen in the Cricket World Cup.
Under a law passed last year, a spectator carrying a product made by a competitor of one of the main sponsors of an event is liable to have it confiscated.
In the Cricket World Cup, this has meant that sports fans with cans of Coca-Cola have had them taken away as they enter grounds, or confiscated by stewards walking through the crowd during matches.
Spectators have been allowed to take in bottles of mineral water but only if they remove the label.
T-shirts, hats and flags bearing the logos of sponsors' competitors have also not been welcome.
South Africa is the only country in the world where ambush marketing is a criminal offence.
It could help in South Africa's bid to stage the 2010 Olympic games - big firms might be more likely to offer financial support if they know their investment will be protected.