Some people are using a way to alt by changing their name in the account they are banned and create a new account with the same name with which they got banned.If a player joins the server they can only change their name after 30 days of playing,which would prevent/not allow the alters to that.
An example of a player who used this as a way to come back in his old name:
https://imgur.com/a/4jkmLlw
https://imgur.com/a/yHpklhu
https://imgur.com/a/NSOLOEu
https://imgur.com/a/iEulrBU