Show connection id everywhere where the user name is shown
Again and again someone joins only to spam the chat or do other nasty things. At least one of those guys impersonates someone regularly playing on the server making it hard to figure out, who the offender is, sadly causing the regular player from being kicked some times. This could be prevented by having the connection id of the offender being shown all the time (in the kick-vote it's shown already, but only there).