SAO PAULO The Brazilian tradition of the concentracao - sequestering teams before matches and shielding them from temptations such as sex and alcohol - is under threat as players take a stand against the late payment of wages.
So far this year players at Botafogo, Portuguesa and Vasco da Gama have refused to attend the concentracao because their salaries were not paid on time.
Although only Botafogo's players have maintained the boycott, their action has led to a reappraisal of the ritual and raised questions over the integrity of Brazilian players.
"Football is all about results, and if Vasco and Botafogo can show that they perform better without the concentracao then other teams will adhere," said Lucio Surubin, the director of football at recently relegated Nautico.
"But it is hard. If I had responsible and conscientious professionals I wouldn't have any qualms about ending the concentracao. But I don't."
The concentracao is a long-standing institution used to control players. Teams gather in hotels or at the club training ground for one or two nights before matches so staff can monitor the players, prepare them for games and keep them away from outside influences.
Botafogo's players rebelled at the start of the year. The club had not paid their salaries for several weeks and the players abandoned the concentracao in protest.
The experiment proved successful and continued even after their salaries were paid.
The Rio de Janeiro side have had one of their best seasons in years. They won the Rio state championship in May and finished fourth in Serie A, guaranteeing a place in next year's Copa Libertadores for the first time since 1996.
One of the club's veterans, central defender Bolivar, said they know the spotlight is on them and they look out for each other.
In Brazil, fans regularly monitor which players are spotted socialising in the days before matches, a task made easier by social media.
"We don't spy on each other but we're aware that we've been given a vote of confidence and we need to respect that and live up to it," Bolivar, the former Monaco player, said. "This can only work when you trust the players."
Bolivar added that when European players learn of the concentracao "they think it's crazy".
Even in Brazil, the practice has long been considered anachronistic. In the early 1980s, Corinthians midfielder Socrates called it a "notorious aberration" and the then medical student organized shifts the day before a match to avoid being involved.
He led his team mates to vote against the practice and they rejected it for several years during a period known as Corinthians Democracy. However, when he left the club in 1984 the concentracao returned.
Other players have legendary tales of escaping the bubble.
Garrincha sneaked out of the Botafogo team hotel during a 1959 tour to Sweden, and nine months later was rewarded with a son.
Renato Gaucho missed out on the 1986 World Cup after being caught partying on the eve of the tournament.
Romario and a young Ronaldo left Brazil's team base one night during a Copa America tournament. After scaling a wall, Ronaldo was surprised to find Romario had arranged a taxi to take them to a nightclub. "It was mega-professional," he joked years later.
Nevertheless, many players acknowledge the practice does serve a purpose.
"The concentracao allows the team to be together, to talk over the game, to watch videos of opponents, and to relax," said Moises Moura, a central defender with Portuguesa whose itinerant career has taken him to clubs in Portugal, Russia, Qatar and China. "These kind of things keep you focused on the game."
But he added: "In Brazil, where there are two games a week almost every week, there is a certain attrition.
"You spend more time with your team mates than with your family. Players need downtime to get football out of their heads and take the pressure off."
Other players said some Brazilians are not responsible enough to be left to their own devices.
If the team are playing well fans overlook transgressions, but when the results go against them there is a backlash.
Brazilian supporters regularly harass and abuse players and sometimes even attack them when the team is struggling.
Corinthians fans recently chanted slogans against Romarinho after he was spotted socializing. Fans at Vasco did likewise with Rafael Vaz in October when they suspected him of going out on the eve of matches.
Vasco players boycotted the concentracao for several games earlier this season when the club was behind on paying wages, but they have since returned. Vasco were relegated last week.
Only time - and money - will tell if more teams follow the lead of Botafogo, or even if the Botafogo players' stance continues.
Bolivar said he was enjoying having more time with his family but doubted whether many clubs would voluntarily adopt Botafogo's approach.
"Botafogo are pioneers but not every team can do it," he said. "I think the majority of players aren't ready for it. They have friends, they go out, they aren't all responsible. The mentality here is different. I think it will take some time."
(Editing by Stephen Wood)