To be an Authority Masternode, a person must have three main characteristics:
(1). Public Identification
Authority Masternode validators need to confirm their real identities, which must be well known within the community. Each validator has to go through a strict know-your-customer (KYC) procedure.
(2). Have a Good Reputation
Because of such public identification, it means Authority Masternode validators should be ready to stake their reputation and money on the project. It is their identities and reputation placed at stake that give all the Authority Masternode validators additional incentives to behave and keep the network secure.
(3). Meet Standardized Criteria
An Authority Masternode validator must meet the minimum criteria set by the system. Thus, the method for selecting validators must be equal for all candidates. Who sets these standard criteria? Of course, they will be set by the creators of the blockchain who want their creation to be successful.
These three criteria are quite strict, hence, only a few people end up becoming Authority Masternode validators in POA system.