Point of fact, my friends.
Fighter pilots can only risk a rearm- which entails sitting perfectly still for thirty seconds or more- if there is relatively no hostile threats nearby. Otherwise, it is suicide. Thus, if you're flying a resupply ship, then you're likely only going to be deployed when the coast is clear.
Of course, there are exceptions, like the support pilot who had to race in and load some more Helios bombs onto Alpha 1's Bakha while the Sanathas was cranking out the long-range flack. But, situations like that are part of the job- I think of Huey pilots in Vietnam who would often risk heavy fire to resupply beleaguered troops with much-needed ammunition.
Considering that rearming friendly ships with secondaries could easily make a huge difference in a fight, I think it's reasonable to assume that both the fighter pilot and the supply ship pilot would both take the risk of re-arming with hostiles in uncomfortable proximity, if the situation demanded it (bombers coming in and the interceptors need Trebs, or bomber pilots short on bombs.) Being a supply ship pilot is not as dangerous a job as a fighter pilot, but it's not a cakewalk, either.
