Re: Re: idn-uri document

In draft -03, it says:

     For domain names containing non-ASCII characters, the Nameprep
     specification ([Nameprep]) defines some mappings, which mainly
     include normalization to NFKC and folding to lower case.  When
     encoding an internationalized domain name in an URI, these mappings
     SHOULD NOT be applied.  It should be assumed that the domain name is
     already normalized as far as appropriate.

Why the "SHOULD NOT"? What's wrong with a system that creates URIs doing that?

An alternate wording for the last two sentences would be:

     When encoding an internationalized domain name in an URI,
     these mappings do not need to be applied if the domain name is
     already normalized as far as appropriate.

--Paul Hoffman, Director
--Internet Mail Consortium