I. The consent of the victim to conduct constituting an offense is a defense if such consent negatives an element of the offense or precludes the harm sought to be prevented by the law defining the offense.
II. When conduct constitutes an offense because it causes or threatens bodily harm, consent to the conduct is a defense if the bodily harm is not serious; or the harm is a reasonably foreseeable hazard of lawful activity.
III. Consent is no defense if it is given by a person legally incompetent to authorize the conduct or by one who, by reason of immaturity, insanity, intoxication or use of drugs is unable and known by the actor to be unable to exercise a reasonable judgment as to the harm involved.