Problem sorted. I introduced a cron job that puts up regular messages, one of which says:
Console: Please don't keep changing to the winning team or you'll be banned
I haven't had to ban anyone yet ![Grin ;D](Smileys/dp2/grin.gif)
Usually, if the Hud/Text Scale option is big enough, that part of the MOTD will be completely gone from the console, from either the option being so high, or more console text comes up.
Something to think about.