People occasionally join and post to many threads in the for sale area. My suggestion would be to at least go through and lock the ones that have been sold. People do not seem to read the threads before posting to it. Or there may be a number of other ways to address the problem, if you want to address it.
Locking them is a PITA. First, the user that posted needs to report it sold and they rarely do. Then the staff has to keep checking to see if someone posts that it is sold. On my site I created a job that moves items out of the main sales areas and into an archive 90 days after the thread was started.
You are correct, but I did want to bring the topic to your attention. We have things set up where anyone can start a thread, but no one can add to it. That also solves the problem.
I absolutely agree with abomination. They should lock it. Although gnatster has a point also. I guess what we all want is to make the flow smooth Good Day everyone.