I have reviewed this document as part of the security directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written primarily for the benefit of the security area directors. Document editors and WG chairs should treat these comments just like any other last call comments. This document talks about the practice of mandating some forms of URI sub-structure in documents, which use existing URI schemes. This document is arguing that such practice is inappropriate, because that essentially usurps ownership or URI sub-structure from URI owners. This document further describes some acceptable alternatives for use in standards. I agree with the Security Considerations that this document does not introduce new protocol artifacts with security considerations. I think this document is Ready.