Rugby: Football looks over its shoulder
The answer would appear to be: a considerable amount.
With the rugby World Cup reaching its climax in Sydney today, senior soccer men have taken note of how its distant cousin handles things, so to speak; and sponsors have also registered rugby's 'cleaner' image.
Despite the greater physicality of rugby, and in spite of the darker side of the game which includes eye-gouging, stamping and fighting, sponsors are re-considering their options.
Recent events in soccer including alleged unsavoury incidents in hotel rooms, failed doping tests, a player charged with rape, and all sorts of assorted drugs allegations across Europe, have all tarnished football's image.
Aigner, UEFA's chief executive said this week that soccer could improve its disciplinary image by following rugby.
"I'd like to change things in refereeing most prominently. I'd like to bring in a stricter line with more discipline, like the discipline used in rugby, to bring ethics in and disallow players from showing a bad example. When I was a referee in Germany we had the sin-bin and that worked."
The sin-bin works in rugby by taking the heat out of a situation and allowing a cooling down period without penalising one team with a dismissal for an entire match for a relatively minor offence.
But what is most noticeable in rugby is the respect for the referee, which is almost totally lacking in soccer.
In rugby, the referee's decision is final. In soccer, it is usually the signal for the start of an angry foul-mouthed argument.
"We absolutely have to stop players encroaching on the referee," said Aigner. "One of the things I'd like to do is that, before a player can become a professional and sign a contract, he has to pass the referee test.
"He would be obliged to have a few matches as a referee so he understands what it means to be a referee and behave in the right way."
Robson has also been impressed by what he has seen of the rugby World Cup.
"Some of today's professional footballers could do a lot worse than follow the example of Jonny Wilkinson, on and off the field," he declared.
"I think Jonny Wilkinson is an ideal role model for everyone in sport, especially youngsters. I wish we had more like him in football."
Robson was hugely impressed when Wilkinson scored all of England's points in their 24-7 semi-final win over France in Sydney last weekend.
"To kick all of England's points was a truly memorable achievement. He's comfortable with either foot, though he kicks naturally with his left. I think he's got a left foot like Ferenc Puskas. It doesn't get much better than that, does it ?"
Puskas, of course, masterminded Hungary's 6-3 victory over England at Wembley 50 years ago next week the first time the England team lost at home to foreign opposition.
Soccer has changed enormously since that memorable match and not always for the better.
PR consultancies, advertising agencies and other marketing men are beginning to target rugby players for commercial potential in a week when a survey by a consumer research company found when a player misbehaves outside his sporting arena, consumers are less likely to buy the goods he is sponsoring if they are deciding between two identical products.
Sponsors are noticing this and are increasingly looking at rugby players to endorse their goods. Now, eight years after their sport went professional, rugby players are beginning to move into the millionaire bracket.
Wilkinson, for example, is promoting cars, watches, a bank, beer and soft drinks and will earn around £1.5m this year before his rugby salary is taken into account.
Rugby will never match soccer's global popularity, but it does do some things a lot better.
Rugby players do not feign injury or dive looking for penalties. They respect the referee. The game allows an advantage to be played, but if no advantage eventually accrues, the referee takes the play back to the original foul and re-starts the match with advantage still with the side that has been wronged.
The one rule soccer has taken from rugby in the recent past is advancing a free kick 10 metres if players continue to show dissent to the referee or attempt to delay the kick being taken. Oddly, the rule is now rarely used in rugby because there is so little dissent.
Soccer will remain the world's most popular sport, but when Aigner and Robson start looking over their shoulders, you know it is far from perfect.