Voluntary Assumption of Risk
The voluntary assumption of risk is a complete defence. The elements of it are similar in are way to contributory negligence, but it is a more complete act and a more complete state of mind, in terms of the plaintiff exposing themselves to risk. The elements are:
The plaintiff had an actual and full appreciation of risk and,
The plaintiff voluntarily accepted it.
When a risk is obvious the plaintiff is assumed to have accepted it. In Scanlon v American Cigarette Company  the plaintiff had started smoking at the age of 15 and, smoking 20 cigarettes per day, contracted lung cancer. The defence was that the plaintiff knew or ought to have known the risk of smoking, and thereby accepted the risk...
ORDER FOR FULL TEXT.
 Scanlon v American Cigarette Company (Overseas) Pty Ltd (No 3)  VR 289.