Hi @Bogdan_Krystek, welcome to the forums.
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Unfortunately, cheating is a huge problem with Zwift in the community races. Some users might not even realize they have a poor setup, or something is wrong, others might be doing it maliciously. There are numerous threads in the forums about the issues with community racing and many good ideas on how to make it better, more fair, etc… but it doesn’t appear that Zwift is sure about how to handle it. They have some beta anti-sandbagging rules/tools in place on certain races, but they aren’t available for event organizers yet.