Personally this is my opinion on the matter, anyone can join the antiscammers, even if they only have one post. However because people know that anyone can join it should not be a basis of trust for ANY transactions. There can be a group of "elite" antiscammers though, ones who would have a different sig and be on a list on the official thread. that would work where you would PM other elite members and ask them if you yourself could be one.