What was that guy doing? When you kill monsters simultaneously you only get XP from up to 8 of them (correct me if I'm wrong). I don't see why he'd need to hold "4-5 camps" worth of monsters. If this guy was grabbing that many monsters for the purpose of leveling up his dudes, this is a weird way to go about it.

Anyway this is getting away from the original intent of your post. Are you complaining about people not "earning" their job levels or is this about fighting over mobs with another player?