Let's say there's a port that ships supplies to the military. Let's say the military is currently in war and needs supplies to do things like fight back and not get killed. Let's say a group of protesters blocks that port as part of a war protest, potentially jeopardizing the lives of the military members who need those supplies. Does this technically qualify the protestors as combatants?
Responses:
General Knowledge
While I appreciate your intent, son, the Geneva Conventions (it's plural) are quite clear on what constitutes a combatant.
The closest the Conventions come to the situation you describe is in the definition of resistance combatants, as follows: ... Members of ... other volunteer corps ... operating in or outside their own territory, even if this territory is occupied, provided that such militias or volunteer corps... fulfil the following conditions:[ (a) that of being commanded by a person responsible for his subordinates; (b) that of having a fixed distinctive sign recognizable at a distance; (c) that of carrying arms openly; (d) that of conducting their operations in accordance with the laws and customs of war.
General Knowledge
Obviously, these 'protestors', even if well organized and carrying on operations that affect the war effort, cannot be classed as combatants unless they are carrying arms openly and have a distinctive sign or uniform. This would not be the case with the people you mention.
Corporal Punishment
They would therefore be classed as Unlawful Resistance, and can be dealt with however the hell we please.