A seemingly innocuous piece of shirt swapping could have serious repercussions for one South American player - and highlights the importance of local derbies in his continent's football.
In an Argentine league game last weekend, Gimnasia striker Luciano Leguizamon exchanged jerseys with Juan Sebastian Veron, once of Manchester United and Chelsea but now back at his original club Estudiantes.
As a consequence of this action, Leguizamon was not considered for selection for the club's next game, played last Friday night, and there has even been speculation he might have his contract torn up.
His problem is that the Gimnasia-Estudiantes match is the big derby of the city of La Plata, its rivalry nurtured by decades of tradition.
To make things worse for him, this gesture of sporting cordiality did not take place with any old Estudiantes player but one who is a veritable symbol of Gimnasia's long term rivals - Veron's father also played with great distinction for Estudiantes. And to cap it all, Gimnasia lost the game.
Veron proclaimed himself bemused by the scorn that fell on Leguizamon. He attacked the hysteria surrounding the incident, which he said could only worsen Argentina's serious problem of football violence.
It is impossible not to agree with him but excesses of local rivalry will be hard to root out of Argentine, or indeed South American, football.
Even more than in most parts of the world, the big derby matches are a fundamental part of the sport's history.
Some 35 miles north west of La Plata is Argentina's capital Buenos Aires.
An extraordinary 12 clubs in the country's first division are to be found in and around the city. Throw in the pair from La Plata and that only leaves six clubs to represent the rest of the country.
This is a familiar pattern all over the continent. Frequently South America's countries have one big city - the port through which raw materials were exported and manufactured produce imported - and an undeveloped hinterland.
The dispersion of football clubs shows this imbalance. Of the 16 clubs in Uruguay's first division, only two are from outside Montevideo.
Of the 12 in Paraguay, eight are from Asuncion and two more are from its outskirts.
The big traditional clubs in Peru are all in Lima, those in Chile are clustered in Santiago.
Throw in another fact - the vast differences between cities - and it is clear that the history of club football in South America is based on city rivalries.
Brazil continues to waste months at the start of the year playing state championships, one for each of the 27 states that make up the country.
These competitions serve no footballing or economic sense and are a serious impediment to the adoption of a rational calendar for the domestic game.
But the existence of a lengthy competition to discover who is top dog in his/her city continues to be dear to the heart of the Brazilian supporter.
Fierce local rivalries have done much to fuel the South American game but there are negative effects on the pitch and in the stands.
It is one of the explanations for the excesses of gamesmanship that can creep into the continent's football. After all, in a local derby, anything goes.
One of the things that former Argentina coach Jose Pekerman would love to change in his country's football is "the fear of losing, generated by a perverse culture in which the fan's only satisfaction comes from the fact that his team wins and so he won't be mocked at his workplace on Monday".
In Brazil, they often say that such mickey-taking is the soul of the game.
The facts seem to point in a different direction.
On Sunday, the biggest crowd of the season - more than 80,000 - went to the Maracana in Rio to see Flamengo against Santos.
There was a small contingent of travelling Santos fans but basically the stadium was full of Flamengo fans.
In theory, the big-city derbies should attract more but fear of violence keeps many at home.
The biggest crowds now tend to be for games when only one group of fans are present.
Perhaps then, instead of being punished, Luciano Leguizamon should be praised.
South American football will not die, and may even thrive, if a little bit of heat is taken out of the local rivalries.
You can put your questions to Tim Vickery every week on the World Football Phone-in on Radio 5 Live's Up All Night programme from 0230 to 0400 GMT every Saturday. You can also download last week's World Football Phone-in Podcast.
YOUR QUESTIONS ANSWERED
Got a question about South American football for Tim Vickery? Email him at firstname.lastname@example.org
Why have Peru never qualified for a World Cup? They are blessed with the talent of Solano, Guerrero, Farfan, Pizarro, Mendoza. Do you think they will qualify in South Africa 2010?
They did qualify in 1970, 1978 and 1982 and were also present in 1930 but I take your point, they're punching below their weight and should do better with the dangerous strikers they have got.
One of the problems they have is there is a real negative atmosphere surrounding them at home.
Peru, more or less alone in South America, has a tabloid press that specialises in stories of footballers getting up to no good.
So it seems the players have become mostly concerned with trying to show they are not up to no good and they have forgotten to play any football.
Their play in last month's two opening rounds of World Cup qualifiers was appalling (lucky to draw 0-0 at home to Paraguay and beaten 2-0 away by Chile).
So they need to get on track. Coming up, Brazil at home. The veteran Palacios has been recalled in an effort to give them a bit more creativity.
A lot hangs on the result, especially as straight afterwards they face the tricky trip to Quito to face Ecuador - a match for which they are preparing a specialist altitude team.
Just wanted to know whether you have been keeping an eye on the Premier League lately because Anderson has been in sparkling form for Manchester United.
He's the full package, destructive and creative, full of fire and flair, a true box-to-box midfielder.
At the 2006 World Cup, Brazil suffered from the lack of invention in their engine room and, in spite of winning the Copa America in the summer, I still feel they need something more than a pair of 'water carriers' in there.
Whereas Lucas and the other hopefuls are still pretenders Anderson is already keeping an England international (Michael Carrick) out of the Manchester United first XI.
Strength, skill and stamina and still 19 - don't you agree that this guy needs a second bite of the cherry after being given half a chance in Venezuela?
In retrospect, Brazil probably wish they had sent him to the World Youth Cup instead of the Copa America.
He obviously will get back in at senior level at some stage. It will be fascinating to see if they use him in the central position that he's playing at United - I only saw the Arsenal game but I had never imagined him filling that role.
For Brazil's youth sides he had been wider and freer, with more defensively minded players guarding the centre.
His versatility will clearly be an asset to Dunga or future Brazil coaches - but will they be brave enough to play him in this position as well as two attack-minded full-backs? Something to look out for.