Not at all, such a blow is a very, very rare occurrence at AFL level and the best medical care is at hand but the risk is unquestionably there. Lower levels of the game have seen players die after similar incidents.
There's also the connection a damaging incident like that can have to future issues, such as the Shane Tuck tragedy.
Head knocks happen, accidents happen, concussions happen but you cannot have a situation where hitting someone in the head and knocking them out is only worth two weeks suspension, no matter what the intentions are.