Missing Exception on DOMImplemenationCSS

Currently the createCSSStyleSheet method under the DOMImplementationCSS
interface does not throw any exceptions.  Should this method throw a
SYNTAX_ERR exception in the case that the media DOMString has a syntax
error and is unparsable? 

Also, Under Section 5.2, the insertRule method of the CSSMediaRule
interface the description for the 'rule' parameter states that it is "The
parsable text representing the rule. For rule sets this contains both the
selector and the style declaration. For at-rules, this specifies both the
at-identifier and the rule content."  Should this actually say something
like "The parsable text representing the rule sets'  selector and style
declaration."? Any at rules would generate SYNTAX_ERR exceptions.

Thanks,

Blaine Brodie