The Elves expect guests to know and abide by their laws (as does any culture). Elven laws are simple:
1) Theft is forbidden
2) Murder is forbidden
3) No treasonous acts
4) Warriors shall obey the Laws of Honor in warfare (only enforced in Elven war)
5) One does not harm or threaten a bard
The Wild Elves deal most harshly with the violations of these laws. They do not use banishment like their mainland cousins, most likely because there is no place to go. An infraction of any of the Laws on Gallan results in the death of the lawbreaker. Though the accused is given a choice in whether they would rather have the issue of guilt decided by a duel or accept the decision of the Council of Three.
The Laws of Honor in warfare are not as codified as the above laws, yet they are understood. There are things that are simply not done. Ambushes are not allowed, nor is interference once two swordsmen are engaged. If one side is grossly outnumbered it is normal for a battle between champions to be substituted for combat. An unconscious opponent is rarely slain, more commonly they are ransomed back to their own Branch, often for an extortionate fee. Attacks are made only during daylight hours, and only during the summer months. Above all any altercations between the Branches are considered secondary to any outside threat and the Branches are expected to come to each other's aid against outside attack.