Nonsense. On the last Darkan campaign against CE, I came home with almost as much gold as I left with, and I was in the field for well over a week with a unit that started at 50 men/700 CS. It's all about going to the right places and shaking down the right people 
There is no guarantee you will be able to loot enough gold to pay for your units. And losing your men on the way home is very painful in expenses. Than I'd rather have everyone supplied with 300 gold, just to make sure.
