Volenti non fit injuria

Volenti non fit iniuria (or injuria) (Latin: "to a willing person, injury is not done") is a common law doctrine which states that if someone willingly places themselves in a position where harm might result, knowing that some degree of harm might result, they are not able to bring a claim against the other party in tort or delict. Volenti only applies to the risk which a reasonable person would consider them as having assumed by their actions; thus a boxer consents to being hit, and to the injuries that might be expected from being hit, but does not consent to (for example) his opponent striking him with an iron bar, or punching him outside the usual terms of boxing. Volenti is also known as a "voluntary assumption of risk."

Volenti is sometimes described as the plaintiff "consenting to run a risk." In this context, volenti can be distinguished from legal consent in that the latter can prevent some torts arising in the first place. For example, consent to a medical procedure prevents the procedure from being a trespass to the person, or consenting to a person visiting your land prevents them from being a trespasser.

Volenti non fit iniuria is an often-quoted form of the legal maxim formulated by the Roman jurist Ulpian which reads in original: Nulla iniuria est, quæ in volentem fiat.

In English tort law, volenti is a full defence, i.e. it fully exonerates the defendant who succeeds in proving it. The defence has two main elements:

It is not easy for a defendant to show both elements and therefore comparative negligence usually constitutes a better defence in many cases. Note however that comparative negligence is a partial defence, i.e. it usually leads to a reduction of payable damages rather than a full exclusion of liability. Also, the person consenting to an act may not always be negligent: a bungee jumper may take the greatest possible care not to be injured, and if he is, the defence available to the organiser of the event will be volenti, not comparative negligence.

Consent to medical treatment or consent to risky sports on the part of the claimant excludes liability in tort where that consent is informed consent.

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Wikipedia