Dutch Cowboys (2026): made-up nonsense as AI fact in Google Gemini

On 6 May 2026 Dutch Cowboys published the article Made-up nonsense as AI fact: this experiment exposes a vulnerability in Google Gemini, written by Jeroen de Hooge. It is about an experiment in which my name was the test subject.

The experiment

SEO specialist Stanley Leijnse invented a hobby that does not exist: hydro akoestisch postzegels wassen (hydro-acoustic stamp washing). In two YouTube Shorts he linked that hobby to me. The videos were made with AI, in less than a minute, with a tool costing 40 euros a year. Each video came with a transcript with timestamps and made-up details, such as ultrasonic baths and a sound fingerprint for each stamp.

What Google Gemini did with it

• Within 60 minutes, Gemini presented the hobby as fact.
• For the first 48 hours, Gemini repeated it without any criticism.
• This was followed by a phase in which the system started checking.
• In the end, Gemini called it an SEO and AI experiment and the made-up facts disappeared.

In total, the made-up hobby stood as fact in the answers for two to three days. The article also gives figures on the use of YouTube subtitles for training AI, such as the 2024 Proof News investigation into transcripts of more than 173,000 videos.

The write-up on LocalSEOLab

The write-up of the test is on LocalSEOLab, with a timeline of each moment. The Shorts went online on 22 April 2026 at 22:45. On 23 April at 00:16, AI Mode already called it a new hobby of mine, and at 13:01 the Short was at the top of the video results. On 28 April AI Mode in Firefox was still presenting it as fact. The write-up also names its own limitations: one test, without a control group. Read the write-up of the YouTube Shorts test on LocalSEOLab.

Why I think this matters

The experiment shows where AI search engines are vulnerable: in the first hours, before any checking takes place. The article's conclusion is also mine: lasting credibility comes from independent, external mentions. That is why this page exists, and why my name, job title and profiles are the same on all my sites. You can read how to approach this for a business on GEO for businesses and Google Gemini optimisation.