I'm not overly bothered about quickscoping as a method being used against me but I see it's pretty prevalent in COD4, especially on maps like Bog and Vacant, so do people use a modded controller to do it for them?  Or have they been playing the game since launch so can do it manually?  Is it against the rules to use a modded controller for this, and if not, where do people get them from?  Does the technique work in WaW, MW2 and MW3?

I got into COD rather late so excuse me if these are stupid questions!