I've been roleplaying in WoW since it was released in europe. At the beginning it was pretty much relaxed and casual RP, nothing too exhaustive... Game mechanics made all battling necessary way easy. However, after a couple of months, i found out that you were not allowed to duel inside the city, while i was trying to solve an IC battle. I had to work the entire battle by emoting. Since then, i believe i learnt quite a big share on battle-emoting. It is not like a ruleset must be enforced (using d20, for example), but some guidelines are mostly necessary.