14.1 Consent: Express, Implied & Capacity

Consent: Express, Implied & Capacity

Doctrinal Foundation: In the law of intentional torts, affirmative defenses and privileges concede that the defendant's conduct met the prima facie elements of an intentional invasion (such as an intentional physical contact in battery, a volitional boundary crossing in trespass to land, or an intentional restraint in false imprisonment), but assert that under the circumstances, the conduct was socially justified, legally excusable, or authorized by the plaintiff. The fundamental common-law defense is consent (volenti non fit injuria—"to one who consents, no wrong is done"). On the California First-Year Law Students' Examination (FYLSE), examiners systematically test the line between express and implied consent, the boundaries of legal capacity, the strict anatomical limits on medical authorization (Mohr v. Williams), the critical division between fraud in the factum and fraud in the inducement, and the jurisdictional split regarding consent to illegal conduct.

---

I. Manifestations of Consent: Express vs. Implied

Consent operates as an absolute bar to recovery for any intentional invasion of person or property. The law recognizes that consent may be communicated explicitly through words or inferred from objective human conduct and societal custom.

                          ┌──────────────────────────────────────┐
                          │       Manifestations of Consent      │
                          └──────────────────┬───────────────────┘
                                             │
         ┌──────────────────┬────────────────┴──────────────────┬──────────────────┐
         ▼                  ▼                                   ▼                  ▼
  [EXPRESS CONSENT]  [APPARENT (IMPLIED IN FACT)]        [IMPLIED BY LAW]    [EMERGENCY MEDICAL]
- Clear oral or      - Objective outward conduct         - Customary social  - Unconscious patient
  written agreement    and gestures                        touches & transit - Imminent lethal peril
- Explicit license   - O'Brien v. Cunard S.S. Co.        - Sports within     - Reasonable person consents
  to enter or touch  - Subjective reluctance immaterial    customary rules   - No known prior refusal

1. Express (Actual) Consent

Express consent exists where the plaintiff explicitly communicates a willingness to submit to the defendant's conduct through unequivocal oral statements or executed written documents. For example, an individual who executes a detailed surgical consent form authorizing a specific surgical procedure, or a homeowner who verbally invites a neighbor to enter a parcel of real property, has conferred express consent.

2. Apparent Consent (Implied in Fact)

Apparent consent arises when a reasonable person in the position of the defendant would believe, based on the plaintiff's objective conduct, overt physical gestures, and the surrounding circumstances, that the plaintiff consented to the invasion. The landmark authority is O'Brien v. Cunard S.S. Co., 154 Mass. 272 (1891):

• The O'Brien Doctrine: An immigrant passenger aboard a steamship stood in line with other passengers receiving mandatory smallpox vaccinations. When her turn arrived, she observed others receiving injections and silently held out her bare arm to the ship's surgeon. After receiving the vaccination, she sued the surgeon for battery, asserting that she inwardly objected to the procedure.
• The Rule: The court held that consent is determined by outward, objective manifestations, not unexpressed, subjective mental reservations. Because a reasonable physician would interpret holding out an arm in a vaccination line as an overt manifestation of consent, apparent consent was established as a matter of law, completely barring the battery action.

3. Implied by Law: Custom & Everyday Social Usage

Civilized society necessitates countless incidental physical contacts that individuals are deemed to have consented to by virtue of participating in community life. Tapping a stranger on the shoulder to ask for the time, brushing against commuters in a crowded subway car or theater corridor, or shaking hands in a business greeting are privileged by implied consent under prevailing social customs.

4. Athletic Participation & Contact Sports

An athlete who voluntarily participates in a sport impliedly consents to physical contacts and collisions that are customary, recognized incidents of the game:

• Customary Collisions Privileged: A football player impliedly consents to being tackled, blocked, and shoved within the ordinary flow of play.
• Violations of Safety Rules Outside Play (Hackbart v. Cincinnati Bengals, 601 F.2d 516 (10th Cir. 1979)): Implied consent in athletics is strictly limited to the rules and recognized customs of the sport. In Hackbart, an opposing football player, frustrated by a turnover, intentionally struck an opposing safety on the back of the neck with a forearm blow during a dead-ball play after the whistle had blown. The Tenth Circuit held that while football involves violent physical collision, players do not consent to intentional, malicious strikes delivered outside the boundaries of active play in flagrant violation of general safety rules. The blow constituted an actionable battery.

5. The Emergency Medical Exception

Where an individual is incapable of providing actual consent due to sudden trauma or illness, the law implies consent to prevent death or permanent bodily harm if four cumulative elements are satisfied:

1. Incapacity: The patient is unconscious, incompetent, delirious, or otherwise physically incapable of giving valid consent;
2. Imminent Peril: An immediate medical or surgical intervention is necessary to prevent death, loss of limb, or irreversible impairment of health;
3. Presumed Reasonable Assent: An ordinary, reasonable person in the patient's position would consent to the life-saving procedure under the circumstances; and
4. Absence of Known Objections: The attending medical providers have no reason to know that the patient, while competent, previously refused the procedure or harbored religious or personal objections (such as an executed advance healthcare directive or known Jehovah's Witness objection to blood transfusions).

---

II. Legal Capacity to Consent

Consent is legally ineffective if the plaintiff lacks the legal and cognitive capacity to understand the nature, quality, and consequences of the physical act. When legal capacity is absent, the defendant cannot invoke the plaintiff's apparent assent as a defense.

1. Infancy (Minors)

• General Incapacity for Serious Invasions: Very young children conclusively lack legal capacity to consent to invasive medical procedures, sexual conduct, or substantial physical violence.
• Age-Appropriate Peer Activities: An older child (such as a 12-year-old) possesses legal capacity to consent to normal, age-appropriate peer contacts, such as neighborhood playground games, touch football, or wrestling matches. However, an adolescent cannot consent to activities involving substantial bodily harm or statutory sexual offenses.

2. Intoxication

Alcohol or drug impairment invalidates consent only if two strict conditions are met:

1. The intoxication was so profound that the plaintiff was incapable of understanding the nature, quality, and consequences of the invasion; and
2. The defendant knew or reasonably should have known of the plaintiff's severely incapacitated state.

• If an intoxicated individual appears outwardly lucid and comprehends the physical invasion, consent remains valid in tort, even if their inhibitions were significantly reduced.

3. Mental Incompetence

Individuals suffering from profound mental illness, intellectual disability, or neurological dementia lack the legal capacity to authorize intentional physical invasions if they cannot grasp the basic physical nature and significance of the touching.

---