To take up arms in a cause is the only defining method in this are any case of this matter.
This same issue (taking up arms that is) comes up when looking at near any war.
No this isn't a personal attack on anyone one, but in fact an attack on the thinking of the argument.
If going by Alan's are now your thinking, one could fire on any type troops, but because your not in a national army; than you can not be held responsible for the actions taken.
If one takes up arms, he has by right made a choice to up hold that cause he has taken up.
On the field of battle do bullets stop as I asked if a person was a non combatant, militia, regular, volunteer?
The question isn't did the men receive a pension, the only question is did they take up arms?
The thinking behind rules & laws, has nothing to do with this issue; those laws are for politicians and lawyers.