The original driver for the development of this standard was European, where national identity cards are common practice. In fact, many of countries are issuing smart cards that contain X.509 certificates (as well as the associated private key). The inclusion of these national identifiers is important to this community. In this situation, the authority is a particular country. I have little concern that a national infrastructure will assign the same identifier to more than one person inappropriately. Another place where a Permanent Identifier can be used is in a company. Consider the employee number. Again, I have no concern that a company will assign the same identifier to more than one person. It would make a huge mess in the human resource database.