There are a few instances where you may wish to use this cheap "tactic", particularly on the Japanese-themed map where the harvester is off on the other end with the rear entry point up against the map end without good cover for an approach. Especially on that map, a lot of aliens are in the "cockpit" room just mulling around (it does seem that the pathfinding routine for the AI is rather weak, because although the aliens appear to know where you are without seeing you, they are unable to come out from the harvester to attack you if they have to "double back" to the aft exit before swinging around the side to get to you). If you are about a dozen squares away facing head-on to the cockpit, you can often spot the aliens inside through the "windshield". The aliens will stupidly try to shoot you through the windshield, and you can get them to expend most/all of their ammo, sometimes even leading to alien friendly fire deaths if the cockpit is crowded. I had my dedicated blaster trooper on the 2nd floor of the opposing main building, looking out the window with "ball" reaction fire set. She ended up taking a couple shots at the aliens too, and surprisingly after her last shot I found the "windshield" gone! I had her take some more "ball" shots, aimed between the two pieces of big "machinery" that block the way to the "cockpit" room. After two more impacts or so inside, I ended up killing maybe three of the aliens before the room emptied out.
On a different map, I used the same tactic to blow out the windshield, then had my grenade-launcher trooper lob PBs inside...instakill. This combined with the bolter rifle "through the ceiling/floor" to hit the 2nd floor "engine room" aft makes harvester assaults very safe, and perhaps too easy (i.e. "cheap"). I know this is an exploit of the AI, and I look forward to the day that AI (in general with all games, not just UFO:AI) gets good enough so that such "cheats" don't work anymore.
