I have always wondered, why we can't see who is banned and who is not. To prevent abuse which you mentioned, temp bans shouldn't be shown, and perm bans should.
I think, best case scenario everybody should see who is banned and who is not. If that's not an option, users who actively reporting should get this privilege, as a small bonus.
I'm not sure what the benefit of knowing this information would be though. If you are reporting one of their posts then it doesn't really matter whether they are banned or not if their post is off topic/spam or what ever as it adds to the clutter of the thread.