I'm sorry but considering you're the one complaining, or at the very least backing up "multiboxing ruins proper pvp", you should provide some definition for the term you're using. As for the fair use, a multiboxer is very limited when it comes to the larger battlegrounds, esp. AV. As with any advantage (being able to basically 1-shot at least 1 person each GCD) there's also a disadvantage (you can't do **** against an enemy that is spread out).