If this trust system works correctly, it doesn't matter if someone spams or not. Everyone can define their own trust lists here. (maybe similar function as #bitcoin-otc WoT gettrust?)
It would be silly if the forums started to remove some trust ratings because 'it's spam.'
Oh? Really? What if somebody negative repped you, because you didn't buy their latest product? Or if they positive repped somebody because it was their alt account, or somebody from their company? Or says, "Positive rep my company, and I'll remove this neg rep"?