CSS Error & Warning free: ! or ?

As I've started "W3C compliant CSS"-issue (http://drupal.org/node/70296) as a wish, it was the first one in the chain of validitaion.

The main critism of warning-free css-validation is the "inherit" argument, which changes nothing visible, but is needed by W3C-validation (warning free).

In my opinion there is a difference between an "explicit defined default" and an "undefined default", cause the "explicit defined" says: Yes, I'm sure, that I want to do this.
As we are experienced webusers, we know that the warning of "undefined color" doesn't make visible sense. But it's one of my most-hated questions customers asks me twice a month: "Why does your site so much validation warnings, although you are working active for accessibility?".

Another important argument is webchick's (http://drupal.org/node/70296#comment-110432), cause it helps debugging CSS problems.

BTW.: I'm currently collecting information to validate Drupal against all "W3C WCAG P1/P2/P3 and Section 508" rules, to eliminate eg.:
- There are 1 form controls that should contain labels. no "label" elements.
- There are no labels for controls.
- There are 6 tables and 6 contain the "summary" attribute but are note data tables (none of them has header cells).
Maybe we should start (if there is a public interest) a own OG "Validation"?

"The CSS2 'inherit' value - available for every property - leads to compact "!important" style rules that govern most or all of a document."
http://www.w3.org/TR/WCAG10-CSS-TECHS/

Some interesting articles for ingheritance:
http://www.blooberry.com/indexdot/css/topics/inherit.htm
http://dorward.me.uk/www/css/inheritance/
http://www-306.ibm.com/able/guidelines/software/swsystemset.html
http://www.access-matters.com/?p=1