I'm not sure why that information would be valuable to spammers. It would only tell them that their posts are being flagged, but it wouldn't really help them get to the front page.
From the point a spammer is identify until their interaction with the system becomes a burden to deal with, it's better to not let them know it's known they a spammer. Craigslist does this by "ghosting" postings that's flagged as spam; that is the spammer sees the posting as live, maybe even gets an automated reply to see how/if they respond, but the general public does not see the posting.