Making accusations of drug use by a sporting hero is a sure way for a journalist to become a pariah to fans.
The most famous example is the campaign Irishman David Walsh ran against cycling drug cheat Lance Armstrong, who then rallied support from people as wide ranging as comedian Robin Williams to Bill Clinton, as Armstrong successfully sued Walsh and the London Sunday Times in 2006 for over $2 million for libel.
Armstrong, as a cancer survivor, was a dream story as he blitzed Tour de France fields. The sad fact, which wouldn't fully emerge until 2013, was that he was a ferocious user of banned drugs. But before his fall from grace he was an inspiration to cancer sufferers, while Walsh, and his sources, one of whom Armstrong charmingly described as "a prostitute with a drinking problem", were seen as jealous nobodies feeding their own egos by sniping at Armstrong, a man whose feet they weren't fit to kiss.
Little wonder then, that when former Irish rugby player Neil Francis floated the idea that the Springboks' triumph at the World Cup might have sprung from more than a brilliant team culture and gameplan, but may have had some pharmaceutical help too, he was slated by South African fans.
But if you read beyond the headlines, Francis gave such explicit details of how sophisticated the cocktail of drugs used by Springbok winger Aphiwe Dyantyi that led to his banning from the Cup team in Japan, it's difficult to believe the 25-year-old didn't have some expert medical help in preparing the steroidal mix. It then follows that Francis' suggestion Dyantyi should be offered amnesty by World Rugby to become a whistleblower makes perfect sense.
The fact is that success will often be a reason to turn a blind eye to drug cheating. Dyantyi is a South Africa based player. Francis noted the example of how a fan favourite there, prop Chiliboy Ralepelle, was able to play out his career for the Sharks despite two suspensions for drug use, and that in a survey by the South African Institute for Drug Free Sport of 12,000 schoolboy players in the KWA Zulu-Natal region it was revealed that 1200 said they had taken steroids.
When a story that warms us all is challenged, it can feel like someone is killing Bambi. We've always loved the vision of Kenyan distance runners emerging from the red dust of the Rift Valley, their genius a legacy of centuries of running as part of nomadic life. How do we reconcile that with more than 40 Kenyan athletes failing drug tests in the four years to 2016?
Sadly it can take years for honesty to emerge about drug use. After the infamous 1986 rugby test in Nantes, when Buck Shelford was kicked so hard in the face he lost teeth, and had his scrotum split by a French boot, he was convinced the French players had been taking drugs. In a 1990 interview about the 16-3 loss he told me, "You just had to look in their eyes to see the buggers were on something."
It took 29 years, but in 2015 the truth emerged when '86 French team doctor Jacques Mobet told journalist Pierre Ballester that it was a time when each player "had their little pill in front of their plates for the meal before the match". The little pills were amphetamines, then so common in French rugby Mobet says a championship club game in the 1970s was stopped by the referee because some of the players were foaming at the mouth.
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History shows that hypocrisy plays a massive part in the story of drug use in sport. Go back to the banning and shaming of Canadian Ben Johnson at the 1988 Seoul Olympics. Loaded with so many steroids he looked, as Arnold Schwarznegger was once so famously described by Clive James, "like a condom full of walnuts", Johnson beat American Carl Lewis to the finish line in the 100 metres, but was stripped of gold within two days after a failed test.
Lewis had been complaining about Johnson all northern summer in '88. "A lot of people have come out of nowhere and are running unbelievably, and I just don't think they're doing it without drugs," he told a British TV interviewer. "If I was taking drugs, I could do a 9.80 right away. Just like him (Johnson)."
Hypocrisy? Through the roof. In 2003 a whistleblower from the United States drug testing organisation revealed old documents that showed Lewis had tested positive to not one, not two, but three banned stimulants at the American trials before the '88 Games. The results were buried, along with positive tests by almost 100 other athletes, by the US Olympic Committee.
Lewis' response in 2003? "It's ridiculous. Who cares? I did 18 years of track and field and I've been retired five years, and they're still talking about me, so I guess I still have it."
The fight against drugs, continuing this week with the weird circus around Chinese swimming super star Sun Yang after he tried to smash vials of his blood with a hammer, often feels like a losing one. But having written a book with an athlete I believe is 100 per cent clean, Dame Valerie Adams, and seeing how devastated she was after a drug cheat, Nadzeya Ostapchuk, robbed her of the joy of claiming a gold medal in the stadium in London at the 2012 Olympic Games, I'll never support drug testing going into the "too hard" basket.
And it will take honest officials and crusading journalists to keep the battle going. Clean athletes are too busy training to lead the charge, while the drug users themselves can live in such a parallel universe they almost need saving from themselves.
At a social function in the 1980s I heard a world ranked field event athlete cheerfully note how she'd tried a stimulant for greyhounds a crooked owner had given her.
Didn't she think that might be dangerous? "Nah, he only gives it to the bitches, and I'm a female too, so it must be okay."
On a much happier note, one of the funnier visions provided by Kieran Read, in an interview with Hilary Barry to promote Read's biography, was how the first time Read roomed with Richie McCaw, hardly a word passed between them. McCaw famously wasn't big on small talk, and Read was too intimidated to initiate a conversation.
My favourite All Black rooming story was told on himself by Justin Marshall.
New to the team in 1995, the then 22-year-old rookie halfback found himself sharing a room in France with Zinzan Brooke, already established as a legend at No 8.
Casting around for something to say, Marshall asked, "Zinny, what's that under your left eye"?
"It's a birthmark", replied Brooke.
Brief silence. And then, said Marshall, "How long have you had it"?