White combo color on black background is fine. Black combo color on white background (while silly and I'd advise against it) is also fine. Black on red is fine. Combo color is a rule, you can't have it blending into the background.
ziin wrote:Breaking any rule warrants a DQ.Since the map stays readable there's nothing wrong. And you said yourself that combo colors doesn't need any rule.
Breaking any rule warrants a DQ. However combo color isn't a rule. So there's no broken rule here. -> Abusive disqualification.