That scene always got me. The other scene from that movie that gets me is when the Germans round up all of the children in the camp and load them in to trucks. As the trucks start to drive away with the children crying and screaming for their parents, the mothers who have been lined up in the yard first appear confused and then, finally realizing what is happening, they begin to break formation in a mad rush to the fence to try to save, or say goodbye to, their children.
The scene of the little girl in the red coat always seemed to be contrived, at least until Schindler then sees the red coat again in a pile of bodies.
Technically, it wasn’t a movie, but the last scene in “War and Remembrance”, when Natalie finally finds her son probably made me weep more than anything I’ve ever seen.