I have to ask, why? I mean, what's it to you if someone comes in, makes whatever requisite posts (or better yet, becomes a dues paying member, which you don't appear to be currently) and then simply uses the classifieds?
I guess I've never really understood why anyone cares what anyone else is doing. It's no skin off your nose and if they are paying a subscription fee, it actually supports the site. If nothing else, if they are just cruising the ad sections all the time, they are getting just as much site advertisement coverage as anyone else does, which pays the bills.
I've been a site supporter for quite some time. My year ran out around Christmas and with work ramping up due to the cold haven't paid it up yet.
My whole beef in my response is with those who don't close ad's after selling. I don't care if they come as long as they pay or follow the rules.