The decision, rendered last week, ruled Johaug out of next year's Winter Olympics in Pyeongchang after she had tested positive for an anabolic steroid in September 2015.

The three-time Olympic cross-country medallist successfully argued she had unknowingly ingested the substance in a sun cream used to treat acute sunburn on her lips but CAS were damning of her complacency and, indeed, negligence, for not scrutinising the list of ingredients closely enough.

CAS were right to be so critical. After all, the package in which the product came in was marked in big, bright red letters accompanied with a clear message "DOPING".

Warnings do not come more stark than that.

CAS said as much in their verdict. "Having reviewed the matter in full, the Panel noted that Ms Johaug failed to conduct a basic check of the packaging, which not only listed a prohibited substance as an ingredient but also included a clear doping cautionary warning," a statement read.

Presumably, Johaug is not stupid. Why, then, did she not double and triple check what was in the substance she was applying?

Why would she take that risk?

In the current sporting climate that we live in, where there is more intense pressure than ever on anti-doping authorities to catch the cheats, surely you would take every precaution possible before using or taking anything you had not put into your system before.

Johaug, a member of Norway's Olympic winning 4x5 kilometres relay team at Vancouver 2010, insisted her doctor gave her the green light and said that she would not fail a drugs test. Even then, she should have made absolutely sure.

After all, the substance the 29-year-old failed the now fatal test for - an anabolic steroid - is among those which carries the most severe punishments under World Anti-Doping Agency (WADA) rules.

Some may view her sun cream claim as a rather lame excuse, yet the fact remains CAS agreed with her. In their ruling, they said she had committed an anti-doping violation with "no significant fault", and as a result the maximum sanction she could have got was two years.

The case echoed the one involving Maria Sharapova, the Russian tennis star banned for her use of her meldonium, a substance which gave WADA plenty of self-inflicted headaches. She was also given the same verdict when she had her suspension reduced from two years to 15 months following an appeal in October of last year.  

For a start, they were both found to have been careless rather than cheats. 

They were also both given poor advice by those in their inner circles; Sharapova's team and Johaug’s doctor.

As the political scientist Roger Pielke Junior points out in an excellent post on his website, that is where the similarities end. In fact, the way the two cases were dealt with by CAS could hardly have been different.

Pielke highlights these differences in a comparison of the full written decisions from the CAS regarding the two athletes.

On the subject of responsibility, the CAS wrote "it is an athlete's primary duty of care to read the packaging of products and to double-check with a medical person if the information refers to a prohibited substance" when delivering their verdict on Johaug.

There is no mention of "primary" care in Sharapova's. Instead, CAS said: "An athlete can always read the label of the product used or make internet searches to ascertain its ingredients, crosscheck the ingredients so identified against the prohibited list or consult with the relevant sporting or anti-doping organisations, consult appropriate experts in anti-doping matters and, eventually, not take the product.

"However, an athlete cannot reasonably be expected to follow all such steps in each and every circumstance."

It is that last line which enhances the argument. If Johaug was expected to carry out stringent and thorough checks, why wasn’t Sharapova?

"The Panel finds it striking that Ms Johaug did not perform the most important of them…it follows that a top athlete must always personally take very rigorous measures to discharge these obligations," the CAS decision on the Norwegian adds.

Contrast this with the one on the five-time Grand Slam champion. "…nothing prevented the player, a high-level athlete focused on demanding sporting activities all over the world, from delegating activities aimed at ensuring regulatory compliance and more specifically that no anti-doping rule violation is committed".

The differences are striking and are perfectly summed up by Pielke when he writes: "In my opinion there is a troubling degree of arbitrariness in the CAS sanctions".

Often the decisions of CAS, such as those given to Sharapova and Johaug, blur the lines when it comes to defining a doping cheat.

Some will still class the two as dopers. One is serving a ban and the other has served a ban.

But both cannot, going by the CAS verdicts, be described as intentional cheaters.

Undoubtedly, they should have known better and should have been far more careful. I am sure that, given the chance to turn back time, they would do so without a second thought.

Yet equally they both deserve little sympathy. They know the rules and whatever the circumstances, they broke them.

As Pielke and others have suggested, the Johaug case also shows the CAS is not perfect and could certainly use an overhaul in some areas.

Anti-doping Norway chief executive Anders Solheim told newspaper VG that, while Johaug could have no real complaints, the way in which they went about it poses questions for the future.

"I can not say there is reason to say that," he said when asked if Johaug was treated unfairly.

"There has been a process in both the judicial committee in Norway and in CAS, and I think they have been as expected.

"But CAS should be an open court and one should look at the selection and composition of judges in CAS.

"People should get full insight when someone is convicted of violation of doping rules.

"And those who judge should be completely independent of sports organisations. It is not so everywhere today.

"Even in CAS, all things go for closed doors."

The door is also firmly shut on Johaug's hopes of competing at Pyeongchang 2018, where she was aiming to clinch her first individual Olympic title.

By the time the Beijing 2022 Olympics come around, she will be 33 and beyond the peak of her powers.

Johaug's chance at Olympic glory has been left shattered. Her dreams have been dashed.

And she only has herself to blame.