CSS validation of a:visited

Recently, I ran into a snag and took a bit of time to figure out why my
CSS construct

	a:visited { text-decoration: none }

wasn't working.  (It turns out the answer is explained here:)
https://hacks.mozilla.org/2010/03/privacy-related-changes-coming-to-css-vistited/

(Yes, it's really "vistited", not "visited" above.)

It appears most, or maybe all, browsers adhere to the prohibition of only
allowing a limited subset of CSS actions in "a:visited" for security
reasons, even though it is legitimate CSS, but it took me a while to
figure this out.

I wonder if perhaps your CSS validator might better serve the public if it
checked for and issued a warning when encountering such CSS constructs.