www.DON'T_TYPE_ANYTHING_WITH_$DECODE_IN_IT_GOD_DAMNIT.com
and
www.DON'T_RANDOMLY_TYPE_ANYTHING_SOMEONE_TELLS_YOU_TO.com
That should cover it.
If you see the words /write and $decode in the same line typed by anyone, report it to an ircop and ban the person if you are opped in the channel.
