About 7 years ago I almost lost the tip of my finger flipping open one of these
http://spyderco.com/catalog/closeup.php?product=211 using the hole in the blade; not a problem with my older Endura with the plastic handle but the extra weight of the stainless model caused my middle finger to move just a little too much ......... blood sprayed all over the wall and ceiling !
Off to the Emergency room ; I still have no feeling in that fingertip .
Live and learn.