Dumb business people with stupid, lazy business practices.
Nearly as bad as dumb lazy pilots. Part of any trip going to remote-ish areas is fuel planning. Deciding where to refuel. Which airports have bowsers, which brands, are they 24 hour swipe. Figuring out if you have what you need to buy fuel - carnet / visa card / cash. Planning how your arrival time fits with the airport's fuel arrangements. I used to plan to arrive at Olympic Dam when the Shell fuel handlers were still there.
JR - this probably isn't actually the guy's job. Not many places sell enough Avgas for someone to live off the proceeds. The refueller probably has a real job in town that he needs to leave when you call him (or her; DF) out.
But specifically for Cobar, reference to ERSA tells us that the call out fee only applies AH. It also notes that the fuel is provided by Aero Refuellers who have a 24 Hr swipe bowser. Aero refuellers are really easy to deal with. I just don't understand why you would fly through regional NSW without one of their carnet's.
So, if the pilot a) plans to fuel at Cobar without checking the fuel availability (ie reading ERSA), b) requires fuel after hours and c) hasn't had the foresight to arrange a carnet for the 24 Hr swipe bowser then an $85 call out fee looks pretty reasonable to me.
As for the $2.60 per litre, that's about a 12% premium over capital city prices. Its an ugly price, but for the costs of getting it to Cobar and dealing with our byzantine AVGAS regulations, 12% is not too bad and may be comparable with the price premium of Mogas in the township