The problem is Rob that .ES treats some registrations differently. Check out
Article 2 of the .es Dispute Policy . The pdf is in Spanish, but this specifically gives government agencies and public bodies like the postal service, more power to recover their (or confusingly similar) .es domain.
These are powers which the standard .com udrp doesn't have. The confusingly similar applies to use
inside Spain, not just wether it is a generic dictionary word.
IMO it would be tough to convince a one man, govt appointed panelist, that
www.correo.es and
www.correos.es are not causing confusion.
Sorry to take the shine off your appraisal thread, but I see this as a possible tm typo, albeit with high traffic, and very slight end-user options in Spain.
You may prefer to see it differently, but that's the nice thing about appraisals...