This is not to say that every player who takes advantage of the liberalisation of international qualification rules that has swept through sport over the years is motivated by profit. Being adopted by a country with which you may have only a vague genetic connection can often prove to be a natural union of souls that were always meant to be together.
Yet the path between nationalities is not always smooth and free of pitfalls. Vinnie Jones may find that the Welsh who enthusiastically welcomed him to their careworn ranks a couple of months ago will not be delighted to find that cannibalism is now listed among their national characteristics.
The Republic of Ireland, on the other hand, have absorbed a selection of diverse dialects and personalities into their football team with spectacular results. There are those who feel that the way they play lacks a touch of the unpredictability that would make it wholly Irish in nature, but no one could begrudge either the players or the Irish supporters the pleasure and glory they've had over the past 10 years.
The Irish example was probably the main trigger of the recent spate of activity in sport's version of cross-dressing. We've seen rapid re-births in soccer, rugby union and rugby league. But it is not a new phenomenon and neither has it been confined to team games. In tennis, for instance, the most notable switch of allegiance was made 30 years ago by the old Australian eccentric Bob Hewitt. But he had a good reason. Australia refused to pick him any more because of his antics and he ended up playing for South Africa.
The need for the top tennis players to have a nationality at all is probably less than it has ever been. The Davis Cup is no longer the big event it was and to represent one's country does not appear to be a priority of top stars who trudge around the world like displaced millionaires.
In golf, the opposite is happening. Professionals in what can be the loneliest, most self-determined game have in recent years been wrapping themselves in flags and embracing the team ethic with sobs of pride. That they are making good money out of standing to attention for the anthems must temper our admiration for their patriotism but they do get genuine pleasure from representing their country.
In the ultimate golfing team event, the Ryder Cup, they play totally for the love of their nation or, in Europe's case, their continent. Because of the superiority of the Americans, the Ryder Cup was acquiring a deathly pallor until 15 years ago when the USA's original opponents, Great Britain and Ireland, strengthened themselves by taking in the rest of the continent. We overcame the loss of national pride by pretending that Seve Ballesteros and Co had become British rather than we had become European. Nevertheless, the move represents the only successful example of European unity in recent times.
The Ryder Cup has long been eyed enviously by top golfers from other countries - the South African Simon Hobday once claimed that he qualified to play for Britain because he was born in Mafeking - and that is why some of us fortunates were gathered on a warm Johannesburg evening last week to witness the opening ceremony of an event that intends to take a firm grip on the Ryder Cup coat-tails.
The Alfred Dunhill Challenge between Southern Africa and Australasia has many reasons for its creation, not least the sponsor's wish to mark the spread of its luxury goods business to South Africa. Nor would the company mind if its founder's name could be perpetuated like Samuel Ryder's has.
The players' enthusiasm also has a considerable commercial tinge. It opens up many other possibilities of international matches before massive television audiences and brings a mega-buck World Tour closer. And, unlike their Ryder Cup counterparts, they are getting paid for standing around neat and tidy in their team blazers and not in a democratic way either - Greg Norman, Nick Price and Ernie Els, for instance, are getting $170,000 and the fee reduces in order of reputation to $25,000.
There is, however, an undeniably strong feeling of team spirit about them this weekend. These players can earn big money every week but they confess that they want to experience the type of battling spirit they see embodied in the Ryder Cup. They have not had to change nationality to do so but they have accepted a grouping of their flags with others and they talk of an even wider representation by forming a Southern Hemisphere team to challenge the Northern.
That might be taking the breaking down of boundaries a little too far. There is much to be gained as a spectator by having an allegiance to a player, a team or a country. But it is difficult to foresee a group of Zulus, Aborigines and Maoris getting together to chant: "There's only one Southern Hemisphere." There is a limit to what can be simulated and I doubt if you could ever artificially create the deep rivalry bequeathed by historical enmity upon which most of the great sporting events are founded.
It was an outbreak of patriotic snarling that did much to sharpen up the Ryder Cup recently. The players doing battle in South Africa today seem too friendly ever to get to that stage. But if international competition can add so much to the sporting scene there can be no harm in its increase.
With countries becoming more of a racial mix, old qualification restrictions were meaningless anyway and dropping them can certainly raise the general standard of play. The fact that the Wales and Western Samoa rugby league teams are suddenly able to pick better players will make a resounding difference to that code's World Cup in October.
However, there is a limit to how far we should allow these liberal attitudes to go. In Sweden they permit any player who plays in their ice hockey league to be selected for the Swedish national team. In theory, therefore, it would possible for Sweden's team to consist entirely of Czechs. That sort of freedom opens up possibilities too terrible to contemplate.
Whatever happens there will always be sportsmen happy to go where the demands are and to ask not what they can do for their country, but what another country can do for them.
WOMEN'S professional tennis recently took the extraordinary step of refusing to accept a lucrative sponsorship offer from Tampax on the grounds that it might offend the other sponsors they collect on their way around the world.
They happily take money from cigarette and drink firms but become all coy about a product that is fairly basic to womanhood. I hope other women's sports will not be so sensitive.
At the very least, it will be a useful reminder that not all sportswomen wear jock straps.Reuse content