My question is, would you rather it not be mentioned to a person if the thread already exists? Does it annoy you guys when it is pointed out as much as it annoys the person making the duplicate post?
I think all registered users of FR could stand to read this post by Jim Robinson, but I doubt all will follow it, sadly. More work and waste for FR.
I doesn't matter to the moderators one way or the other if duplicates are pointed out on a thread. If that is the practice you choose, it would be helpful if you pinged us. We would like to be notified if there is a duplicate. We don't always see all the posts, there are just too many to go through.