roncachamp
Final Approach
Probably because they'd have to change all the charts and other printed materials.
Sectionals change every six months. IFR charts and the A/FD change every eight weeks. I don't see a problem.
Or maybe just so that they know roughly where you're calling from.
When you call and say, "Green Bay Radio, Airmaster 83289, receiving Janesville VOR", they know you're near Janesville. When you call and say, "Green Bay Radio, Airmaster 83289, receiving Mackinac Island RCO", they know you're near Mackinac Island.
If you're near Janesville or Mackinac Island, and the guy you're calling is in eastern Virginia, why should "Green Bay" be part of the callup?