Question - is this at the top because you've pinned it there, or because people voted it so? I've been around here for 6-ish years now, and don't think I've seen any pinned mod comments before.
Of course, a truly Evil™ company would have both options available: a visible icon for transparently pinned comments, but also the ability to invisibly pin a comment to influence readers. There is no real foolproof method, unfortunately.
All pretty cynical, though.