Is it bad form to embed meaning in unique identifiers?
The NIEM Naming and Design Rules (NDR) refers to ISO 11179 as guidance for good data definitions. Typing information within a data definition (such as "7 digits" and blocking ranges that refer to various kinds of accounts) is considered TERRIBLE practice by ISO 11179. All NIEM data XML elements are typed elements and carry only typing needed for representation (NIEM can use constraints and/or patterns when required). The definition for an ID should state the meaning of the ID and/or its use; not define it through its specific typing and business rules. NIEM has other fields for data examples and detailed description of usage if needed.