Approved and Implemented Ideas i can think of that can prevent/avoid scams are the following:

- Live Chat Support (which i think is the best out of the 3)
the fact that not everyone has knowledge of how the site works especially with their Middleman Service is a major factor as to why there's a scam like this happening. Having a Live Chat Support would dramatically decrease the victims of these scams b'coz new members can ask Community Moderators about their questions or concerns and they will get an immediate answer with explanation.

- Guides/Walkthroughs for Newly Registered Members
this one can be done through Private Conversation Ticket. Newly registered Members will receive an Auto-PM that includes guides/walkthroughs with short but clear explanation (not like the words you used in your original seller/buyer guides & knowledge base) about the site, contacts and how your service works.

- Forcibly Enable-Lock Notifications on Disputes, Help and Middleman Sections
Implementing this will make everyone receive notifications every time there's a new thread created in that 3 sections. It can be the Disputes section alone just to make everyone aware of what scams/disputes are being reported everyday.


Additional...

- Create a Site-Staff List page

 

I also agree, thats actually what i was thinking when im writing it up and yes you understood it right, every members would get notification when a dispute is created.

Now i just thought of an idea on how this method may not look as an annoyance, all Verified members can disable notifications from the dispute section if they wish to while non-Verified cannot. ( as for me, i still prefer getting notifications even though im already an experienced seller. )

To put it in a perspective, for a member who already knows what they're doing this method may or may not be seen as annoyance as well as for a new member but has experience selling in other sites but i think that for a completely newbie seller this would make them aware of all the scams that are happening every so often which i think for every new sellers is much better than experiencing the scamming theirselves before they do their research about the scam reports in the site. Wouldn't they'd be more glad and grateful that they received all those notifications than getting annoyed that it saved them from any scam attempts?

Im not sure if i get all my explanations correct or if its still vauge but if you do you can tweak as many as it take to make it more eye-pleasing rather than eye-pissing.