Underscore in META NAME value

As of today it would appear that the NAME attribute value in a META tag can
no longer include an underscore.  For example the code '<META
NAME="Date_Created" CONTENT="2001-05-15">', which never produced an error
before, now produces 'Error: character "_" is not allowed in the value of
attribute "NAME"' when using the W3C HTML Validation Service.  Is this
correct?  It is not identified as one of the corrections in the CVS log.

Dave
-- 
D. J. Blackwood