There is only one way to do that. Make reputation on your server matter.
No account bound stuff, and no transfers off a server.
When people become afraid of being black listed by the community.
Because if they are forced to start over on another server, losing everything.
That would be something that almost all would fear happening to them.
That fear is the only thing that will make people behave.
If there is a easy way out keeping everything, and changing servers.
It isnt going to matter to a lot of people. In order to keep them in
line, it needs to matter.