I feel like posting offtopic now, but it's actually on topic so here is my question:
Having a fact I am an FPS noob... When someone crouches and is still crouching as well as moving fastly from point A to point B that his body is not moving at all while still crouched, also being able to shoot me. Is that considered as some kind of lag, or hack? I've seen that quite a few times since I had my day off to play BF3.