They may seem like they're tying troops' hands behind their backs — especially given that today's wars are very different from those when the former laws of war were written — but there's a good reason why certain rules have been imposed to protect troops in combat.
Though not every country ratified all of the protocols of the Geneva Convention, and fewer still signed the Hague Conventions of 1899 and 1907, many still hold to the general provisions and restrictions.
The laws of war contain a lot of things that make sense. Don't hurt civilians. Don't attack places of worship or medical aid. They may seem small at first glance, but they are a line US troops cannot cross.
While the major laws of war are well known, there are some provisions that may surprise the average reader.
#1: Filing down your bullet. (The 1899 Hague Declaration IV,3 and Geneva Convention Protocol I Art. 35)
There is always the loophole of "military necessity" — that's why flamethrowers are okay, because they have an actual purpose if used on foliage and clearing tunnels.
So while hollow points are legal, filing down a bullet to make in improvised dum-dum round is a no no. The purpose of doing that is to cause unnecessary harm.
So that 5.56 round some jackass took a Multi-tool to to "make it hurt more" committed a serious offense.
#2: A chaplain picking up a weapon. (Geneva Convention Art. 24)
If troops become shipwrecked or parachute out of a destroyed aircraft, they now have non-combatant status. They're technically out of the fight.
The most protected service member in the ranks is still the chaplain, who should never enter combatant status.
Regardless of their denomination, chaplains have a duty to uphold the spiritual, moral, and religious well-being of everyone on the battlefield. They will enter combat zones, but only to provide aid. To date, 419 U.S. Chaplains have died in war and eight Medals of Honor were bestowed to chaplains.
It is a part of their duty to never lose non-combatant status to help the needs of all. Picking up a weapon immediately revokes that status. If you ever wondered why armed chaplain assistants are so valuable, that's why.
#3: Taking war trophies. (Fourth Geneva Convention. Art. 33-34)
There's a fine line between taking a souvenir and pillaging.
Anything you take off the battlefield is pillaging — even if it belonged to an enemy combatant. It is subject to strict regulations after it's turned over for inspection and clearance. If it's a weapon, it must also be made unserviceable at the expense of whomever is taking it back.
Stashing it goes against tons of laws.
#4: Putting a large Red Cross on your equipment for combat operations. (Geneva Convention Protocol I Art. 85)
The Red Cross, Red Crescent, Red Crystal, and Red Shield of David are all protected as the international symbol for medical aid. When it is painted on a vehicle or on an armband, it lets everyone know that they are only there to render aid. Like chaplains having protections, so too do medics if they are performing aid and evacuation.
If a combat medic takes up arms, they lose their status as a non-combatant, which has been the norm in modern conflicts. If they drop their weapon to give aid, they regain that status.
But the red cross symbol doesn't give you noncombatant status. If the symbol is on a piece of equipment, such as a first aid kit or pack, it is only signifying that the contents are for first aid.
#5: Not protecting journalists. (Geneva Convention Protocol I Art. 79)
War corespondents are just as protected as any other civilian on the battlefield. They must never pick up arms or else they losing their status. The difference between members of the press and other non-combatants is that they are required by their job to be in the middle of a firefight to report what is happening.
In the modern era, journalists have been easier and more valuable targets than ever. If one is embedded in a unit, no matter how pesky and nosy as they seem, they are valuable assets to the war effort and still must be protected.
#6: Insulting prisoners of war. (Third Geneva Convention. Arts. 13-16)
Writer's Note: For the final point on this list, there will not be a photograph of a prisoner of war, regardless of nationality, in reference to their mistreatment.
One of the goals of the Hague and Geneva Convention was to protect the rights of prisoners of war. They must be given medical attention (Art. 15). They keep the civil capacities they had at the time of capture (Art. 14) and must always be treated humanely (Art. 13).
The definition of humane treatment covers no physical mutilation (including torture). This also means you must provide protection from acts of violence, intimidation, and verbal insults.
It doesn't matter who the person is or what they did before they are captured, they are now a prisoner of war.