Why really should you warn or even ban for annoying names? What if it is his real name and he doesn't want to change it? What's then?
— Why warn it?
— It was before seeing the rules of the group
— Read the rules
— Sir please change your name
— I'm not the only one with strange names here.
— Change it please :)
— Thank you, much appreciated
— If your name contains fifty unicode chars you should scream at your parents