The COVID-19 pandemic caused an interruption in Brazilian soccer in 2020. Since early July, the presence of fans at stadiums was strictly forbidden by law. The literature states that crowds' pressure could result in a referee's bias against the away team and increase the home team's pressure to score goals. Using a sample of the four 1st leagues’ main regional leagues of Brazilian soccer, we found, at best, mixed results regarding yellow cards issued in games played before and during the COVID-19. One effect in line with the literature is that derbies are associated with less home advantage than other matches, regardless of the pandemic.