Just as many typical RPGs teach us that violence can solve most problems and that a (truly) dead enemy poses no problems, LARPers around my area (Moscow, Russia) are typically very quick to kill characters of other players, showing very little respect to the lives of sentient beings (not saying "humans" to avoid fantasy racism).
It is common to just go your way on a road and be killed by robbers who just wanted to take your couple of coins, and the robbers can turn out to be noble warriors. Non-lethal weapons are usually not even present in the combat system. Most conflicts are resolved by armed combat, and armed combat usually goes until one side is fully disabled, and being disabled usually means that death is just a matter of time, perhaps it will happen right away, perhaps it will happen after being questioned.
Experienced players develop response measures to this. They try to get as many defensive bonuses as possible so it is harder to disable them, e.g. automatic town portal when they get hit, or try to generally buff their combat stats as high as possible. They try to strike first, and always finish their opponents to prevent potential revenge, which in turn would make themselves finished. They move in huge squads so that fewer entities are actually dangerous for them.
Experienced players used to playing murderous cretins enjoy this, the victims of the murderous cretins typically don't enjoy losing their characters and the need to wait for a respawn. Stupid character deaths essentially remove players from the game for no in-game reason, which is obviously very frustrating.
It is worth noting that behaving like a murderous cretin in LARP is more disruptive than a similar behavior in tabletop because in LARP a real player loses their character and stuff, not an NPC.
The canonical question about casual violence in tabletop RPG has some awesome solutions for this problem in tabletop, but a lot of the solutions aren't applicable to LARP because they rely on the GM being in control of things -- he/she is not in control when a LARP event begins.
- The GM often doesn't even know that something is happening until it has already happened and too many players know.
- Rewinds are frowned upon and considered to be the worst possible offence against player agency.
- There are no NPCs to serve as an example because the few NPCs that are present are not enough. Even if NPCs show disdain about anti-social behavior, other player characters are usually OK with casual violence. If played by a really charismatic leader, such an NPC could possibly override some of the players' decisions, but that is, in my opinion, not an NPC's job.
- Players don't care much about local laws because law enforcement is usually a very hard thing to do. If a criminal isn't caught red-handed and changes clothes, unless someone knew the player IRL, it is very unlikely that somebody will even recognize him. Just changing clothes makes you indistinguishable. There have been a few very rare cases when law enforcement had ultimate powers and was done by NPCs (e.g. if the palace guards announce that you are arrested, you are assumed to be automatically arrested with no chance to escape or fight back).
- Also, sometimes players don't care because they are the law. There is nobody capable of punishing High King's bodyguards who went on to earn some extra coins on the road and have slaughtered 15 people during that time, half of which were young women.
- There is unlikely to be any revenge, as there are usually no witnesses of the murder, and people actually finish victims of armed robberies for this exact reason.
- Most player characters don't care about murder being a wrong thing because the players don't care. I would like them to care, though.
- Since killing anything that discomforts you is more effective than not killing it, players have no actual reason to change their behavior.
- A murder doesn't look like a murder. There is no blood, there are no internal organs falling from a cut abdomen and no enemies trying to keep those internal organs in place: it would be too hard to physrep this unless the murder scene is scheduled, which is typically not the case. Scheduled murders most likely mean an NPC death, and even players who value character life often tend to neglect NPC's lives.
- Another important reason is that players typically avoid roleplaying being wounded if they can avoid it, they just sit on their knee silently (our way to physrep being wounded or dead), don't plead for mercy, they just silently accept the death of their character.
- Moreover, a player roleplaying being wounded too well is likely to be asked if they are actually hurt and get the game stop for a moment. This could probably change if more players were OK with such roleplay, but since it's rare, it causes this unneeded reaction. Also, it does happen that a player gets hurt, and I would probably opt to keep my players asking if everything is OK.
It should be noted that just killing everything on your way typically doesn't give any mechanical advancements. People casually kill to resolve conflicts even when it is not necessary, to remove witnesses and to take the property of the victims. Killing certain designated NPCs (like monsters) gives loot, but they are not to be valued too much.
It is also worth noting that game masters are usually not supposed to interfere in the gameplay once the game begins, so any measures are to be taken in advance. It's possible to write rules and to enforce them, it's possible to talk to players before the game, but, unless something extreme is happening, in most communities a GM shouldn't come to a player and tell to change their behavior.
So, as the host of the event, how can I prevent players from behaving like a bunch of murderous cretins?
By requests from comments:
- Characters are usually not transferred from game to game even if they survive. It is rare to have LARP series, but this happens, and there are a few successful LARP groups that only play in series. So you can call it "one-shot". Some series begin unpredictably: one successful game happens, and its game masters decide to host a sequel game, allowing the players to use their old characters.
- Because of the usual one-shot nature of the games, a lot of weird stuff often happens at the end of a typical game, making continuing the plot harder.
This problem generally persists from setting to setting and I don't see a correlation here. I have mostly played fantasy, but a zombie LARP where I basically was an NPC had this problem too. To be exact, here is a list of settings where I have seen it:
- Innistrad (part of Magic: The Gathering)
- Vampire: The Masquerade (I was myself a murderous cretin there, but it was fully in-character; if you know the setting, my Humanity was around 3-4).
- The Elder Scrolls
Probably worth noting that I did not encounter this at the only Dragon Age LARP that I've attended, but that doesn't automatically mean that it didn't happen -- just that I have not seen it. This game also didn't include much personal conflict, it was more about the Blight. I could presume that a game being focused on an external threat partially solves the problem, but this needs further testing.
- The number of players attending a given game can be very small (like 50-60 players) or very large (1000-3000 players), but the "murderous cretins" behavior seems to be most common at the biggest projects and more rare on the smaller ones. An "average" game is typically attended by several hundred players (200-400).
- The NPC crew is usually not big, as it is not feasible to have a big one. Generally about 1 NPC per 10 players or less. Should be noted that some NPCs are typically non-combatants, meaning that they don't have the skills/health/equipment to meaningfully participate in combat. Combat encounters against NPCs usually involve either "dungeons" where there is a limit on the number of entrant PCs to ensure that NPCs have strength in numbers, or "powerful monster" encounters, when a powerful NPC monster roams the area and looks for problems (the NPC uses this power to compensate for the quantity disadvantage here).
- Players usually design their own characters themselves unless the game is particularly small. The range of their roles and nature is huge, it is not really possible to define it shortly. Some major characters can be created by the GMs, some can be canonical characters from a universe that the game is based on (e.g. most LARP about The Witcher has Geralt of Rivia as a PC), but players can normally ask to have something changed.
- Many types of combat can happen. It might be a duel of honor between two characters (rarely), or a small group of 5-6 bandits ganking one passer-by, or two squads of 10-15 soldiers fighting each other in open field, or a huge epic battle with two to three hundred participants per side (even if there are more players there, they don't usually rush into combat at the same time). There are two semi-important ones that are probably worth noting, though.
- Army combat, a model simulating a clash between two big armies. In this case, this squad of 10+ soldiers (sometimes rules dictate 15+) represents a huge state army. The difference between a crowd of 10 (or 15) characters and an army is that armies have a number of "respawn points" used to revive their fallen soldiers, so dying as a soldier there doesn't make your character dead. Another rule often (but not always) exists and tells that anyone or anything that is not an army and is attacked by an army is automatically hit.
- Combat versus NPCs. The difference is that NPCs usually shouldn't really try to win -- they try to create a challenge and die against the players in a way that makes players feel overcoming this challenge. It is rare to die against NPCs, but it can sometimes happen, like a total party kill (TPK) in a dungeon. Also, as noted before, when entering a dungeon, there is typically a limit on how many players can enter so that the NPCs have a quantity advantage and can be swarming the PCs (as noted above).
- An interesting addition: player characters are also often ready to kill themselves, for example, if they are going to be interrogated and have a risk to give away some important information. The decision to commit suicide is (gladly!) a very hard one in real life for real people, but not for the LARP characters. It creates a vicious circle where characters don't value their lives because it is easy to lose it on the road and kill themselves, and because human life isn't valued, it gets even easier to kill others without a strong reason, and easier to get killed.
- As the players represent the most active part of the game world, game masters are usually not supposed to interfere. However, sometimes it is still needed. E.g.:
- When a player character addresses a deity with their prayer, a deity can sometimes answer through a game master, and even give them something tangible.
- Players entering a dungeon can get comments from the dungeon master like "You enter a dark, dark cave with stone walls. You see lyrium veins in the walls here, and those white strings look like spider web.".
- Some supernatural powers need the player to talk to the GM so the game master can name the effect.
- When players get, say, daily resources, they typically get them from "regional gamemasters", those responsible for a particular area in the game world.
- When a player does something that is against the rules.
- When a player does something really disruptive.
- When a player's physical (or, sometimes, even psychological) health is in danger.