I don't know if this is related or not, but wanting to level my blocking I thought it would be clever to collect a bunch of Greydwarves in a pit, drop myself into the pit, and proceed to block the endless assault and gleefully watch my block rise.

THey didn't attack. Not a one. Once i had them in a confined space they just looked at me over their shoulders and walked endlessly in place against the walls of the pit.

I wonder if there is some kind of ai algorithm that keeps them from attacking if they don't have a pathway out of an area.