This is a role-playing game, where the mechanics of the game reflect the reality of the game world, so obviously 1. Gameplay and personal preferences would require meta-gaming, which is illegal, and explicitly called out in the book as such.
The setting establishes the premise, with the dragons and magic and whatnot, and areas not explained as deviant should conform to our expectations (based on reality, or genre convention, or whatever) . If this is a world where you can kill someone with an arrow by not hitting them with it, then they need to say that. If this is a world where you can be injured by an arrow, but the wound heals on its own within an hour, then they need to say that. Otherwise, the game designers have failed spectacularly to tell us why reality is acting so unexpectedly here.