The co-designer, David Pulver put it this way:
Do you think there should be any penalty for characters who try to use ranged attacks in melee? Like maybe a -2 or something? Just to further distinguish the brawlers from the shooters and give the former a little advantage when the fight gets close?
I guess this would come up in the other OSR games too, but while some refs will rule a longbow can't be used in melee, with guns or super powers obviously they can.
I admit to being of two minds here; maybe it would make a good "optional house rule" or something.
This is how it is currently written up in the Guardians rulebook:
There is a +0 “to-hit” bonus for ranged weapons utilized at short range (x1), a -1 “to-hit” penalty at medium range (x2), and a -2 penalty for long range (x3) attacks. Aiming for one interrupted round adds +1.
Ranged weapons have a -2 “to-hit” penalty at point blank or melee range.
Aiming, with sights for one interrupted round, adds +2.