One trader, Liyana Nasir, 27, set up a stall with her parents near Masjid Jamek LRT station, hoping for some side income from the thousands of supporters expected to attend the demonstrations.

“Sales have been good, as expected,” she told an FMT reporter, adding that authorities did not notice her stall. She was not aware of the ban on vuvuzelas, which became notoriously popular during the 2010 World Cup football tournament in South Africa.

One PAS supporter, who wanted to be known only as Pakcik Ahmad, said he hopes to sell about 10,000 vuvuzelas today.

Although a staunch supporter of PAS, whose party colour is green, Pakcik Ahmad will change into a red or yellow shirt to appeal to his customers.

“When I am near the Red Shirts I will wear a red shirt, when I am near the Bersih 5 supporters I will wear a yellow shirt, but deep down, I support PAS,” he said.

Last year Bersih 2.0 chairperson Maria Chin Abdullah said the reform group decided to ban the use of vuvuzelas because of the noise. The din from the vuvuzela-blowing crowd, especially when political leaders were speaking, made it difficult for organisers to control the situation.