I certainly agree.
That's why I think we should add "risk" to balance out the
potential "payoff".
The worst that can happen now is that a spammer's spam just
doesn't work very well, and he doesn't end up as highly
rated as he'd like.
I'm proposing that the "risk" be that he doesn't end up being
indexed AT ALL. This would actively discourage people from
even experimenting with ratings manipulation.