I'd have to disagree, he's doing what others have to earn by abusing the system in place. While other players are running around looking for players there is a small time frame there where a booster is able to keep killing, this gives them a large advantage and makes up for when a legitimate pker goes out and kills two players, but those players run in a building and they have to go find new targets.

Edit: Sorry for bumping this crappy thread, but boosting shouldn't be let off easily, even if it's already common knowledge that someone is a booster.