Majoru Oakheart
Adventurer
Except that's not how math works. A 5% chance of something can happen 20 times in a row. It's random. The only way to know how it would have happened if you followed all the rules is to actually follow all the rules. Saying that things happen only precisely statistically is even worse. Sure, each monster does a critical hit 5% of the time...so what if they made 19 attack rolls before this combat started? Does that mean that all of them are suddenly "due" their crit and they all crit the first attack this combat?The outcome of a DM- arbitrated encounter should be indistinguishable from what would have happened if it had played out following all of the rules. One-in-twenty chances are allowed to happen, about 5% of the time.
Literally any result you decide on that doesn't involve rolling the actual dice is purely fiat, made up by the DM. It isn't "what would have happened if it had played out following all the rules". You can look at the rules and say "This is one of the likely outcomes", but there's no way to know 100% what would have happened if you followed the rules. Not only that, but even following the rules there is so much variation in what could happen based on the actions people within that battle choose to take. If one of the caravan drivers in a battle hides instead of fighting, suddenly the combat is completely different since he is not contributing to damage. If the goblins drop a huge net on the caravan from above, surprising the caravan and hindering their attacks and movement while they peppered them with arrows, suddenly the combat is completely different.
Without the PCs around, I argue that all of that ceases to matter anyways. Because rules don't govern stuff the PCs aren't there for. Instead, you determine whether a goblin is capable of cutting off someone's head and whether the swing of their sword does so. You don't determine the number they need to hit and the amount of damage they do.
Yeah, if you are assuming the rules are the physics of the world. Which they really shouldn't be. The rules are an attempt to simulate a reality while still allowing the game to move forward at a decent pace. You could roll for broken bones every time someone attacks, but it would take too long and would get boring and would hinder the storyline of the game. So, it's unwanted in a game simulation where the players might be the target of these effects.Tying it back around to the original point of this tangent, though, it would be inconsistent for an NPC soldier to come out of any off-screen conflict with a broken arm or leg. There is no way to apply the combat rules such that (slow-healing) broken bones are a result. (Unless you're using some sort of optional rules for critical hits or something, at which point it applies equally to PCs and NPCs.)
However, the goal of the entire system should be to simulate and actual living, breathing world. Which means that the same sort of things that happen in real life DO happen to people in the game world. Just not all of them happen to the PCs.