This will replace the default TEXT output if someone uses the colour of your background as the colour of any of their text. Output may need to be tweaked to match your theme.
Oh yeah this might be a bit messy but oh well.

on ^*:TEXT:*:#:if ($regex($1-,$iif($len($color(background)) == 1,$+(/,$chr(3),$chr(40),0,$color(background),$chr(124),$color(background),$chr(40),(?=[^d]),$chr(41),$chr(41),/g),$+(/,$chr(3),$color(background),/g)))) { haltdef | echo $chan $timestamp $+(<,$nick,>) $regsubex($1-,$iif($len($color(background)) == 1,$+(/,$chr(3),$chr(40),0,$color(background),$chr(124),$color(background),$chr(40),(?=[^d]),$chr(41),$chr(41),/g),$+(/,$chr(3),$color(background),/g)),$chr(3) $+ $color(normal text)) }