Using separate field-names assures that the different syntax doesn't "leak" into normal headers, but it isn't strictly necessary if implementations always convert back to the correct form when giving it to peers or consuming software that doesn't understand this.
Using separate field-names assures that the different syntax doesn't "leak" into normal headers, but it isn't strictly necessary if implementations always convert back to the correct form when giving it to peers or consuming software that doesn't understand this.