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Kleros Court cases that made history.

Case #122 - Wrong Product Delivered: Dog Food Instead of Cat Food (Court V2)

The jurors decided to uphold the claim because the case is quite clear: the consumer purchased cat food but received dog food instead, which constitutes a breach by the provider. Although the consumer opened the bag before noticing the mistake, this does not deprive them of their right to file a claim, especially since they had previously purchased from the same seller and trusted that the correct product would be delivered. Furthermore, the provider acknowledged the mistake but did not offer an adequate solution, attempting to justify its position by arguing that the package had been opened, which has no legal basis. Therefore, it was decided that the provider must refund the money, while the consumer must make the product available for return, with the provider bearing the corresponding costs. Read more on Kleros Court V2.

Case #123 - Cancelled Excursion and Failure to Issue a Refund (Court V2)

The jurors decided to uphold the claim because the provider clearly failed to comply with the agreed terms: the consumer paid for a full excursion that never took place, and although the provider acknowledged the mistake and that the money should be refunded, it only reimbursed a small portion, approximately 15%, and delayed the remainder without justification. Furthermore, it attempted to rely on a refund policy allowing up to 90 business days, which had not been properly disclosed and, even if considered valid, had already been exceeded by a significant margin. Throughout the process, the provider made payment promises and agreements that it also failed to honor, further aggravating its responsibility. Therefore, it was decided that the provider must refund all outstanding amounts to the consumer, potentially including interest and additional compensation, since it failed to provide the contracted service and also failed to issue the refund within a reasonable timeframe. Read more on Kleros Court V2.

Case #119 - Flight Cancellation and Compensation Claim (Court V2)

The jurors decided to partially uphold the claim because the airline unilaterally cancelled the ticket reservation without providing a clear explanation or evidence of the alleged fraud, which constitutes a breach and a failure to fulfill its duty to provide information to the consumer. However, since the company refunded the ticket price and the cancellation occurred well in advance, the claim for a substantial compensation amount in euros based on European regulations was not considered valid, as those regulations do not apply in this case and no specific damages were proven. Therefore, although the company is considered to have acted improperly, the offer of a smaller compensation amount, such as a goodwill gesture, was deemed reasonable. Read more on Kleros Court V2.

Case #101 - Damaged Luggage and Airline Compensation (Court V2)

In this case, the consumer filed a claim because their luggage was damaged after a flight, and the airline refused to compensate them, requiring the original purchase invoice for the suitcase, which was considered unreasonable. The passenger provided clear evidence, including photos of the damage, official forms, and proof that they had to purchase new luggage. The jurors considered that the airline had breached its obligation to deliver the luggage in good condition and had also treated the consumer improperly by creating obstacles to avoid paying compensation. Therefore, the claim was upheld, and the airline was ordered to compensate the consumer for the replacement value of the damaged luggage. Read more on Kleros Court V2.

Case #82 - Travel Insurance Coverage for Infection During Pregnancy (Court V2)

A woman with health insurance became seriously ill during her pregnancy while traveling abroad, developing a kidney infection that required urgent hospitalization. Although her policy covered medical emergencies abroad, the insurer refused to reimburse her expenses, arguing that the condition was a pregnancy-related complication. The jurors disagreed, explaining that the illness was a serious infection rather than a typical pregnancy-related condition and that it was not listed among the policy exclusions. They also noted that the insurer provided contradictory explanations. Consequently, they concluded that the situation was covered and that the insurer had acted improperly by denying the claim. Read more on Kleros Court V2.

Case #532 - 2020 US Presidential Election Omen Market

In December 2020, the outcome of an Omen prediction market asking “Will Joe Biden win the 2020 United States presidential election?” was challenged and ended up being ruled by Kleros arbitration. A lively debate occurred on social media around the validity of the market, as one side argued that the final result could not be known at the time of market resolution. The case ended with a ruling in favor of the “Yes” option, settling more than $2.5M (at the time) of payouts. Read more in this Twitter thread.

Case #302 - Number of US COVID Deaths Omen Market

In August 2020, the outcome of an Omen prediction market asking “Will there be a day with at least 1000 reported Corona death in the US in the first 14 days of July?” was challenged and ended up being ruled by Kleros arbitration. A lively debate occurred on social media around this resolution, as different sources for the number of daily COVID deaths were reporting contradictory data. The case ended with a ruling in favor of the “Yes” option, settling more than $2.5M (at the time) of payouts.

Case #16/#62/#89 - Listing of Baer token on Ethfinex

The Kleros Tokens registry was used at the time to curate tokens to be listed on the Ethfinex exchange in a decentralized manner. The Baer token was rejected because the community was able to prove that the project was a scam:
  • Their CTO was fake (a member of a non-existent group at Oxford University, checked with a phone call).
  • Suspicious changes to the whitepaper.
  • Fake social media profiles.
Baer Chain was later classified as a Ponzi scheme by the Chinese government a few months later.

Case #554 - Registration of Kevin Owocki to Proof of Humanity

Proof of Humanity is a Sybil-resistant list of humans that uses social vouching and Kleros arbitration to ensure no fake, duplicate, or incorrect profiles make it into the registry. Kevin Owocki, the founder of Gitcoin, submitted his profile to PoH but was challenged because the policy asked for a “front-facing picture” and he provided one where he was looking at an angle. Long debates ensued to clarify what a front-facing picture meant and what an acceptable angle would be. The profile was finally rejected, but Kevin Owocki was able to submit another one and make it into the registry.

Case #82 - Listing of Grid+ token on Ethfinex

The Kleros Tokens registry was used at the time to curate tokens to be listed on the Ethfinex exchange in a decentralized manner. The Grid+ token was rejected because the community estimated that, even if the project was legitimate, the rules required that the contracts be audited by a third party (and Consensys Diligence was not considered a third party, as Grid+ was a Consensys-incubated startup).

Case #92 - “Is this a Doge or a cat in the snow?”

On July 31st 2018, the Kleros protocol was launched on Ethereum mainnet with a pilot called “Doges on Trial”, a curated list application that relied on user submissions to build a list of Doge memes. The experiment offered a reward of 50 ETH to whoever was able to sneak a cat image into the list. Towards the end of the experiment, an image was submitted and, as it was not challenged during the initial 24-hour challenge period, it was accepted into the list a day later. The submitter claimed that the image was a cat and requested the 50 ETH reward. It was the opinion of Coopérative Kleros that the submitted image did not comply with the payout policy, as it did not “clearly display” a cat as stated in the rules. Coopérative Kleros and the submitter agreed to settle the dispute using the Kleros Escrow Dapp, and the payment was rejected in the end. Read more in the Kleros blog post on this case.