Interesting notes on "true honor",
http://www.luminarium.org/medlit/medheroes.htm one quote in particular "The heroes never fight a foe who is weaker, or in some way disadvantaged." In context, it speaks of discarding weapons to even a fight out, or arming your opponent before beginning a duel.
So... If one were to strip naked, throw their weapons in their pack, and then attack a harvester or two, that *might* be considered honorable. But it would probably just be considered odd.
Usually, heroes are so named because of their fight against odds, not with an overwhelming advantage. In fact, if one persists in only fighting when things are on their side, it's usually associated with cowardice, and the one who finally defeats them becomes the hero.
Granted, heroism is a subset of honor, as many quite honorable folk are not considered heroes. But I think it helps to understand this most common form of honor. The basic definition of honor from the dictionary would support that it is earned from a "keen sense of ethical conduct", and not from defeating defenseless foes, no matter if they feed the war machine.
In support of honor for non-combatants, consider who we honor highly today. Sure, there are plenty of aggressors we honor, but there are many pacifists too.