[idn] Delete requirement [13]?

[Paul Hoffman / IMC <phoffman@imc.org>]

>[13] CES(s) chosen should not encode ASCII characters differently
>depending on the other characters in the string. In other words, unless
>IDN names are identified and coded differently from ASCII-only ones,
>characters in the ASCII set should remain as specified in [US-ASCII].

I still do not see why this is a requirement, or even a desired goal. 
It completely precludes ACEs. If there is a logic for this 
requirement, it should be stated better. Otherwise, this should be 
removed.

--Paul Hoffman, Director
--Internet Mail Consortium