We have it set where an area does not become visable until 15 posts are made. It is where people buy and trade their used items.
We had problems in the past and finally got it cleaned up to where there where no problems. Recently we have been having people make 15 posts in 15 minuts, go right to the market place and begin selling. I have caught a few dealers trying to use the area but the area is for people selling personal used stuff, not items bought for profit. Worse yet we are getting people new to the forum, start selling the vanish after stealing money from quite a few members. It went from a place to dump used gear to a place where people who steal and vendors are trying to get access.
I am getting ready to move to xenforo and I hope I can set it up where it is a little tighter.
We have the busiest paintball trading section in Europe. Proudly we also have the lowest scam rate, and in the case of anything going wrong our mods often get involved personally until a resolution has been achieved.
Its kept in check by a strict set of rules and some awesome dedicated moderators.
What I have had happen once in awhile is someone will come in and do 10 or so sales shipping the item. Later they will sell 50 items and vanish from the world ripping off my members. I catch several of them trying to join with different usernames and email addresses once in awhile.