It was one of the first things I thought when I found theses photos. I'm not sure which sect of Islam it is that does tatbeer but I understand some of them will cut their own kids too.
http://www.youtube.com/watch?v=vjtJBTVPyIE&NR=1It should be pointed out, though, that the head has a large amount of blood in it, and it doesn't take much to bleed from the head area. At work, I've seen residents have falls and end up in large pools of blood which look bad but are not the results of bad injuries, since they've bled from the head. With all of this ritualistic blood-letting, I think it's true a certain amount of strategy is involved. But it all looks great.