I actually disagree. Trust score should only be displayed when relevant, such as any subforum that involves transaction (marketplace) and beginner area where newbs take advantage of newbs. However any subforum that is mainly discussion should not display trust score because that will make people biased, even if it's subconscious. Posts from people in red will carry less weight than the ones in green, which is a bit unfair for these guys, when someone's trust should not be relevant when it comes to a general discussion.
Don't get me wrong, I'm not in support of scammers, but some people are red because only because they had an argument with someone else, not because they actually screwed someone over.
Marketplace, begginers and help and all local boards.
Because there is no newbie section in the locals, and sometimes the trades are out of the trades section.