Re: IDN problem.... :(

I think the issue could be generalized as issue of
"Using non-ASCII Unicode as Entity Identifier" for anything. In here the 
  Entity could mean a personal entity or an organization entity.

We don't have this issue today in Unix login, Email address or some IM 
ID because those system in general allow non ASCII Unicode ID. But once 
some system start to accept Unicode for that, we face the exact same 
issue there. And I do thing it is an issue in the area of "Using Unicode".