If you attack a fuel rat on the job, you can expect vigilante players to make you pay for it. You'll get bounties taken out, much better skilled and equipped players will hound you and blow you out of the sky, and generally pay back the fuel rats' losses tenfold.
You don't fuck with the fuel rats, either by choice, or because the entire galaxy has their back and will run you out of town if you mess about with the emergency service.
@danderson From the sound of it, if the Fuel Rats put out a distress call themselves, the belligerent sides in active combat zones call a temporary armistice to assist them.