User blog comment:Brandon Rhea/Bringing down the banhammer: Best practices for blocking/@comment-4578246-20120315210439

Until around mid-January, I used to give no warnings before blocking people, but, after somebody said that they got "red in the face" as they were unaware of a block, now I do try to give warnings unless if the offense is really serious.

The messages I give when warning people on the wiki I recently adopted, Wallace & Gromit Wiki, are a little bit more harsh than the ones you mentioned, but still nice. When somebody is doing something which is obviously an attempt to damage the wiki, though, they do sometimes need to be blocked immediately.