The complexity of the case lies in the fact that it appears very unlikely Mackay meant to bump Clark high. Rather,he was contesting the ball and the collision happened because he got to the contest fractionally late.
The issue of duty of care in a contest was covered in the tribunal case of Carlton’s Lachie Plowman recently,when it was deemed he should have tried to avoid a split-second collision that concussed Hawthorn’s Jaegar O’Meara.