The one-move rule is the main thing everybody that plays LFS should be at least aware of, but lots of people seem to think you're allowed back to the racing line (before the corner) after making the move. So many times someone will move across to defend - fine so you move back to the outside - and then they move back to the outside themselves moments before hitting the brakes, or worse
whilst hitting the brakes. Dangerous.
You have to leave at least a car's width and a half in my opinion, and even then only move back if you're 110% sure there's room to do so. If you move all the way to one side to defend and the chaser pulls alongside, they can keep you pinned there all the way to the corner if they want - it was your decision to move