Hello,

I would like you all to note that it is, in fact, not allowed to own multiple accounts on the same server.
We aren't very rigorous about enforcing this rule, but this is your warning, to the people who do commit this crime.

But some players have accounts on different servers.
Other players like to share their accounts with trusted friends.
There are multiple uses for this function, and we don't wish to limit them.

It's not anywhere in the terms of service, or rules that you can see, but it is technically against the rules to have alternate accounts in the same server.
As for bans, I guess it depends on whether or not we decide to enforce this rule. It may happen, it might not happen. No moderator will ban a player without good reason, even if the player himself thinks it was not deserved.