I'll admit, many maneuvers can be described as cutting someone off. One so crazy that it would likely cause a collision should never be performed, but I was talking about the low-speed "bumper to bumper traffic" scenario common in lanes dedicated to making a left turn: the reason the gaps are too small for a non-cutoff lane change is a direct consequence of the low speeds involved, say 0-10mph. Imagine cars are nearly stopped for a red light, with gaps varying between 0.2 car length and 0.5 car length (this is much tighter than other parts of the US where gaps while stopped for a red light are typically 1-3 car lengths). I would line the nose of my car to the very front of the 0.5 gap (taking the majority of the risk), signal, cross the lane line within a flash or two, forcing the gap to expand to just over the length of my car, all at just a few mph. This is the type of cutting off I was referring to. And the driver who was cut off has no opportunity to fight; they would if I signaled too early!