Manipulating scaling isn't what I would call an exploit.
If someone "exploits" distress by reducing scaling he reduces reward, so it kinda balances out. It's generally more profitable and better to increase it, but that's also balanced out by the difficulty of the encounter.
There is really very little legitimate use for this.
Your not always close to a city or have a car, also distress is majorly used in Turn-Based related activities very actively and removing it would just hurt it unnecessarily.
Seems like you are re-inventing a wheel, waste of time.
Better go and finish crafting system.