I agree with your view, but don't think “setting a precedent” worries the AFL at all. Tanking, rule changes, priority picks, blockbuster games, the list of “precedents” goes on.
On Jobe: I think he should be stripped of his Brownlow just for the pure stupidity of what he did. He's not some green kid fresh off the draft list, he's the captain of the club, and he should have had more sense. All professional athletes have hotlines they can call, independent agencies that can help verify whether the information their coaches and medical staff are giving them is correct. Olympic athletes deal with this situation on a daily basis. Ignorance is not only not an excuse, it's negligence as well.
As captain, he had a duty of care to those players he leads. That is what leadership is.