How about opening a board opened to only DT members, or also staff members. And when a member is considering tagging a members (positive or negative), the issue is brought to the board and the entire active DT members can brainstorm and decide if it's what leaving a feedback.
This can be limited to only 'non scam' scenarios, to reduce the workload. If a user is proven to be involved in a scam or rip-off there is no issue to deliberate on.