A judge in Brazil has ordered Olympic organisers to allow peaceful protests inside venues after several fans were escorted from stadiums for displaying anti-government signs.
With Brazil's political crisis deepening and the Senate on Tuesday taking up impeachment proceedings against suspended president Dilma Rousseff, many are increasingly taking their political grievances to Olympic events.
Their almost universal slogan, used on handwritten signs and T-shirts and spreading on social media, is "Fora Temer" - a call for the removal of interim president Michel Temer.
But a federal judge in Rio said nothing in special legislation passed before the Games restricts Brazilians' constitutional right to free expression. In a temporary injunction, which can be appealed, he threatened to levy fines of up to £2,460 on anyone who removes peaceful protesters from venues.
The International Olympic Committee bans political statements during the Games and has pleaded with fans not to disrupt competition. The Rio organising committee says it plans to ask the judge to reconsider his ruling and if necessary will make a formal appeal.
"This is a global event and we think and we hope that the stadiums would not become a platform for political debate," IOC spokesman Mark Adams said, adding his group will "absolutely" respect Brazilian law.
Politics inside Olympic venues is not new. At the Sochi Winter Olympics in 2014, the leader of Russia's communist party was told to take down a hammer-and-sickle Soviet banner that he and other politicians held up.
But South America's first Games could not have come at a more politically sensitive time. On Tuesday, Senators are expected to vote overwhelmingly to allow an impeachment trial against Ms Rousseff to proceed.
Mr Temer, who took over from Ms Rousseff in May, was widely booed when he spoke at last week's opening ceremony. His approval rating in polls are about the same as the abysmally low levels as those of Ms Rousseff, whom many blame for widespread corruption in the Workers' Party and for steering Latin America's biggest economy into deep recession.
The protests inside the venues have been sporadic and mostly peaceful but attempts to ban them are to some a worrisome sign of government censorship. On Sunday, a Brazilian volunteer with the IOC said he quit in protest against what he called violations of free speech.
In one particularly graphic example, four heavily-armed military commandos grabbed a seated man at an archery event on Saturday and pulled him from the stands. The action was caught on a mobile phone and shared almost three million times on Facebook.
To get around the ban, some Brazilians have co-ordinated with friends each wearing a letter on their T-shirt so the message reads "Fora Temer" when they sit in groups. Others carry smaller signs hidden in belongings, sometimes fashioned as the emblematic Olympic rings.
Vinicius Lummertz, president of Embratur, the government-run foreign tourism board, said he has no problem with peaceful protests inside stadiums provided the Games are not disturbed.
"It's democracy in action," he said, dismissing concerns that the protests could cast Brazil in a negative light on the world stage. "When you think of the size of this democracy, and the youth of this democracy, it tells good things about us."
Still, he said the protesters do not speak for the vast majority of Brazilians who have grown disillusioned with 13 years of leftist rule under Ms Rousseff and her predecessor, Luiz Inacio Lula da Silva.
"People who were against Temer's platform were millions, then thousands, then hundreds," he said.
"Now they are five or six people who get together."