So if you are not logged in on this forum you will not able to see this red warning on current trust system. Perhaps on future admin will enable trust view for guest. But until that you should create account or logged in(if you already registered).
I know that before users can actually post and create threads here as "anonymous" in the forum without even registering or logging in your account, but you can't do that anymore. So I think what you are asking is doable for our guesses to show the trust scores by default without even logging in. Creating an account right now is the best prevention but I don't think that that buying an account is really that recommended to anyone, I mean by default account sellers are tagged right away just by posting their advertisements you may never really know who to trust even if you can see their trust scores.