This page lists the account rules and the punishments for breaking them.
If someone were to set their profile picture to something inappropriate, the account will have their profile picture blocked.
If someone were to make an account with an inappropriate username, they will be banned.
If someone were to choose a username that inpersonates a preexisting account, it will be banned.
If someone were to make accounts for the purpose of automating them, they will be banned.
Having an account banned will prevent logging in to it, and they will no longer appear on the user list.
If an account has its profile picture blocked, the account user will be the only person who can see it. Changing their profile picture to something else will not unblock their profile picture.