General Legal Principle: Consent and Unlawful Acts

The established legal principle states that a person's consent cannot justify or excuse an act that is inherently unlawful. If the act itself is against the law, consent given by the party involved becomes legally irrelevant (immaterial).

• For instance, participating in an illegal prize fight is an unlawful act. Consent to fight does not shield participants from legal consequences if injury occurs.

Identifying the Exception: Lawful Activities and Consent

The question asks for a situation where consent could be an exception, meaning a case where consent might still be relevant even if harm occurs, or where the act isn't considered unlawful in the first place due to consent.

Option B: Advantage taken in a game of fencing presents such an exception.

• Fencing is a recognized, lawful sport.
• When individuals agree to participate in sports like fencing, they give implied consent to the risks inherent in the activity, provided the actions are within the rules of the game.
• Taking an advantage according to the rules of fencing is part of the sport itself and does not constitute an unlawful act. Consent to play the game makes consent relevant to any actions occurring within its framework.

Evaluating Other Options

• Option 1 (Prize fight) and Option 3 (Aiding and abetting in a game of boxing): Both prize fights and boxing (especially unregulated or prize fights) are often considered unlawful acts. Consent is generally immaterial in these contexts.
• Option 4 (Negligent while sky-diving): While sky-diving involves risk, liability can arise from negligence. Gross negligence can make an act unlawful, and the scope of consent in such cases is limited, making it less likely to be a clear exception where consent is material.

Therefore, participating in a lawful sport where consent is given is the most fitting exception where the act isn't deemed unlawful simply because harm might occur during play.