We have expanded the special rules section of the Rulebook today (as well as this site).
When we introduced pilot Re-Rolls (RR) stat as we wanted the make choosing your Pilots slightly more difficult and give you another consideration - as before the only thing you could really review were their Accuracy - which was pretty easy and straight forward - you just used the most Accurate Pilot and that was that.
With Re-Rolls (RR) now in play, we gave the players something else to consider - do you take a Pilot with high of Re-Rolls stat in a bid to starve off bad "luck" or go for a more dependable Pilot with a high Accuracy (AC)?
Although I personally feel that Pilot Re-Rolls are a good thing because they can be applied to defence as well as offence, allowing you to re-roll Evasion rolls in addition to To Hit rolls - in this way, it is better than pure Accuracy, but also introduces a trade off in that they are limited to begin with.
What Do Re-Rolls Represent?
The precise reason why Re-Rolls exist in the game is to bring in some element of luck and fate into the universe - certain Pilots are said to be "lucky" or may have a guardian angel looking over them (or both). Or it could represent the pilot "focusing" on getting that critical shot!