with new green feedback system , even proven scammers are having green trust ratings under their username, and they can scam users again using their green trust ratings 
Not exactly, an user should not see only the 'trust score'
but also check the user's history and use always an escrow if he does not trust the other part.they think green is symbol of trust
Like this dope
Fooled by the nice color and now out of 0.7 BTC
now its a lot of work for default trust members to spot the scammers and help the community
This happened earlier. I was giving an example how color can fool a newbie. In that case it is even more so as there was very specific rating warning against that very particular trade. Goes to show that they rely mostly on colors and hardly on the text.