I worked in Region 4 (Intermountain Region) of the USFS and people there didn't want to have designators. They like using their last names and the confusion this caused was obvious, but the standard answer to suggestions was "we've always done it this way and don't want to change, we don't want anything to be like it is in California." A regional standard for this is good too see. I can't imagine how anyone could work on a multiple agency incident and convey any meaning to communications by just using their last name. As well, when someone comes from another NF they don't have any idea that "Morrison" is the AFMO on a particular district.
Excellent find, zerg, you are a rock star!