Personally I think it is probably better to leave them up, for a short while at least, if only so the purchaser has a good opportunity to confirm that he got what he thought he was getting?
I think the issue is overly cautious moderating of the FS area, the issue of comments needing to be approved seems excessive, especially when despite moderators seeming to make up around 1/3 of the active members, posts aren't given the ok for several days...