The arbiter shall see that the Laws of Chess are observed (Art. 12.1); Duties include ensuring fair play (Art. 12.2.1) and supervising the progress of the competition (Art. 12.2.5); The arbiter determines when a flag has fallen (Art. 6.8) and rules on irregularities (Art. 7)
Why people argue about this
People often assume that the arbiter's role is limited to simply watching games go by without interference, which they see as micromanaging. However, in reality, the arbiter's duties encompass ensuring fair play and resolving disputes or irregularities, not just supervising progress. This oversight can lead to misunderstandings about their active involvement in game outcomes.