Some people think like prosecutors, some think like defense attorneys, some play it both ways, and some not at all.
.. and mercifully you are not smart enough to ever be either.
If I throw a bottle at a wall in frustration and someone inadvertently walks in front of it and is injured, I can't then claim it was their responsibility to look out for flying objects. In any situation, the law takes into account perceived risks. Had the linesman been injured by a ball in play, that would have been a perceived risk. If I walked onto a rugby field and was injured, that would have been a perceived risk. It is not contingent on a linesman or ballgirl or spectator to get out of the way of a tennis player acting violently. Your defense is a joke.