I wonder if Google's had to deal with mechanical turk style flagging campaigns before. If it's really the case that flagging multiple times helps, I wouldn't be surprised if there's some strange spam flagging patterns under the hood that Google's had to deal with. I know the Warrior Forum would be all over that if business owners could get negative reviews pulled just by a slow and steady hit of locally based 'this review is spam' flags. I'd be interested in seeing some numbers if anyone's got any personal experience.
That's what I figured. Either way, I haven't seen many business owners have much luck with getting reviews removed no matter what they do, so the point's kind of moot.