Q: Why isn't trust moderated?
A: Feedback isn't moderated (except for obvious cases such as pure advertising, hundreds of identical empty/gibberish reports on one user) for the same reason as scams - too much room for abuse.

If you are posting a reply on a thread, and your answer is relevant. Would adding your referral link instead of the plain url be a problem?

For example, you are suggesting service a-dot-com as an answer's to OPs question. Would a ref link (a-dot-com?ref=my-ref) be allowed?