yeah, if you could implement something like this, so that when users are warned/banned, it shows:
also, make it so that the admin can set how many warnings a user gets till they are automatically banned. and this would be a great way to issue warnings immediatly (instead of having to go to MCP)
in the image above, red = ban now, yellow = warn now, green = reset warnings/ban to 0 (unban if user is banned). dont worry about the blue button, its not in use on my board (its the report post/topic button). these images are from a phpbb2 board, but im sure you can find some way to implement it in phpbb3. good luck.