WN, unless you actually burn that variable reserve for the purposes it is loaded...
The line has to be drawn somewhere, otherwise it's MLW/full tanks everywhere. In Australia, most companies have decided that not carrying an alternate for single runways is where that line is, probably because there are plenty of airports for a given aircraft type that may not always have a full alternate available within a reasonable distance. The PIC subsequently determines the actual fuel order based on all the additional bits of info and their experience.
Fuel policies inherently contain plenty of assumptions, and little latitude for variation. My opinion is that
fuel orders are 'bad' when they too have plenty of assumptions, and not much thinking.
I have never, ever been questioned by my company regarding a fuel order, and I am not aware of any other pilot that has been.