All competitive games are played on isolated tournament realm servers; Server logs are recorded and archived for dispute resolution; Replay files are available for review by teams and officials
Why people argue about this
People often assume that if they see a replay file showing an outcome different from what was announced, they can just demand Riot Games change it directly, but in reality, data integrity disputes are handled through official review processes where both teams and Riot Games examine the evidence together to resolve any discrepancies.
