I've never seen a down arrow (405 karma as of this writing). I've been imagining it would look just like the up arrow except upside down? My mouse precision is superior, so I will only be accidentally clicking the down arrow when I'm on my CR-48.
Damn, I've got a long time 'til I see it, then, since I've only reached 136 karma in 192 days. I suppose that means I shouldn't be able to downvote, then. :)