I see a lot of these scammers posting bogus ads to get past the 5 feedback block. Not sure the forum settings/ tools are capable of this but is there a way the first few feedbacks posted by a new members have to be approved ?....Like with Negative feedbacks.

Or if the same user gives another member several feedbacks in a given time frame or in the same day they don't count and flags the accounts. If I recall Bladeforums had something like that years ago.

this may slow them down a bit ...maybe. Just a suggestion