Use of "CS" for 'Serbia and Montenegro'

[Bruce Lilly]

>  Date: 2005-01-10 12:49
>  From: "Peter Constable" <petercon at microsoft.com>

> > Note that it says "codes from [ISO 3166]", so it doesn't make one
> > whit of difference if such a tag is registered in an IANA registry;
> > every 2-letter second subtag is always interpreted per ISO 3166, so
> > to the extent that 3166 can be considered to be ambiguous, such
> > ambiguity is unaffected by registry of any tag with a 2-letter
> > second subtag.
> 
> I don't agree that it doesn't make one whit of difference. RFC 3066 also
> says, "This procedure MAY also be used to register information with the
> IANA about a tag defined by this document," which explicitly is
> referring to ll-CC or lll-CC cases. Since we agree that ambiguity is
> bad, and it seems possible to establish consistent, non-ambiguous usage,
> a registration for "sr-CS" may be used to register information: that it
> is used with one meaning rather than another.

Given the facts:
1. the language-tag "sr-CS" fully conforms with the generative
   mechanisms in RFC 3066
2. RFC 3066 gives explicit rules regarding interpretation of
   both primary and second subtags in such a case

what makes you think that an RFC 3066 conforming language-tag
parser would even bother looking in the IANA registry for
"sr-CS" (which matches the generative mechanisms)?