Please remove the offline mode. I know ill most likely get backlash on this but torrented minecraft players shouldnt have permission to use Bukkit. If you did buy minecraft and you play offline it means you either lost you internet temporarily or you bought it on a internet ready system and transfered it over. EDIT:/// Like i said below maybe there could be an update that would make the auth system better. Maybe with bukkit and mojang being friends they could create a link between them?