There are no "non lethal" weapons in the game - thrown stones break bones and put troops out of action for the length of a scenario.
HE fire will cause casualties - whether warhead size is 0 or not, the code will assign a small chance in any case, and target supression etc can contribute to HE casualties as well.
"casualty" != dead trooper. It covers injured, stunned/shocked, run-aways and others not available during an hour or 2 of battle, e.g those carying injured to the rear etc. it therefore can be considered to cover morale damage as well as physical injuries.
A "Bloody Sunday" type scenario just is not really in this game engine's remit. A scenario with SAS in hiding in a police station waiting for an attack by a Provo ASU would be (just) - though the scale would really be too small for the game engine, such a small-scale micro-action would be better handled in one of the 3D "squad level" RTS games available from other manufacturers where 1 basic unit=1 man that concentrate on SWAT(paramilitary police) or similar low-level (below the platoon level) tactics. Those 3-D squad-level game engines may also cover "arresting" the opposition, baton rounds, CS gas, snatch teams and so on (I would hope a "SWAT" or counter-terrorist type game engine would allow that, and not just blasting away at the criminals with lethal weaponry
! )
The MBT game engine is for "open battle" between 2 military forces in an open war situation. Ie both sides "weapons free".
Cheers
Andy