I don't know about that. It seems to me that every time we stop and "let them regroup", the circle they are regrouping to is much smaller than the where they started from. There is no place for them to hide anymore. Laying Siege to the militants (read as enemy of the Iraqi People), is a time honored tradition in the military. Saves ammo, and save the lives of our soldiers.
Laying siege to them is fine.
As long as Sadr doesn't get out of this alive.
If he gets away with this he spawn many more clones.