It's a fair point, though I'm pretty sure the reason for multiple comments coming up is that the "Post" button remains active after it's been clicked and while the page is loading, meaning that someone can easily click it twice (or more) by accident and submit multiple identical comments / replies. The real solution should probably be to disable it after it's been clicked; hopefully at some point we'll get round to that. In the mean time I do often browse around and clear any duplicate comments up that I spot :)