Would be useful to see those who are legitimate for trades or goodguns, but ofc could be abused.
If you do anything like this, I suggest you make people put a reasonable comment like "Not a scammer, traded with no problems" and "Very helpful when I had this problem" or "I traded him 7 gold bars and he didnt give me the item". Nothing like "i wreck ur rep lolol!11!1" or "OMG UR GAY!!!12", if they did this, lower that user's reputation ^^
Just an idea.