2.1.0. Byzantine Fault Tolerance
Imagine several 13th century Byzantine generals have camped around an enemy city and they communicated with each other only via sending messengers. They have to make a collective decision on whether to attack the city or retreat. However, some of the generals are traitors and may actively work against reaching a consensus.
Imagine that the loyal generals decide to arrive at a census that will benefit the entire community despite the presence of the traitor generals. Thus, the loyal generals are staking their reputations for the benefit of the entire community.
POA uses the same principle, which is now known as Byzantine Fault Tolerance (BFT). The loyal generals are the Authority Masternode validators.
But is this not risky? Would you trust a bunch of individuals to make crucial decisions on your behalf?
POA is actually more complex than just getting a bunch of individuals and entrusting them with managing a blockchain.