Put a loving password, pm it to people who want to help.
or
Have the server rules addon and put as one of the rules "Hey, if you don't want to get banned permanently for the day don't do this."
and
Put in the ban reason why they were banned and that they will be unbanned tomorrow.
also
Don't just ban people because they aren't doing anything.
also
Give warnings.
Problem solved.
and known problem-user part
Weird thing is I'm not a problem user and I got banned on sight.
I got my name after this, and 25 is my favorite number.
Let's not forget how Thorfin turns up in a Google Search
naming it after something doesn't make it better