Copyright 1965, American Law Institute
§ 78 EFFECT OF OTHER'S MISTAKE
The privilege intentionally to inflict upon another a harmful
or offensive bodily contact or other bodily harm for the purpose of preventing
or terminating the other's intrusion upon the actor's possession of land
or chattels is not affected by the fact that the other reasonably but mistakenly
believes that he has a right or privilege to intrude, unless the actor
intentionally or negligently causes the other's mistake.
COMMENTS & ILLUSTRATIONS: Comment:
a. The rule stated in this Section applies to cases in which the intruder reasonably but mistakenly believes (1) that he is the owner of the land or chattel or is otherwise entitled to the possession of it, or (2) that he has the license of the possessor, or (3) that the person from whom he has a license is the possessor of the premises or the chattel and, therefore, entitled to give him leave and license to enter or deal with it, or (4) that circumstances exist which otherwise afford him the privilege to enter the premises or deal with the chattel. It is immaterial whether the mistake is one of law or of fact. It is equally immaterial that the intruder's mistake is one against which no precaution on his part would have guarded.
1. A reasonably, but mistakenly, believes that he is the owner of meadow land which actually belongs to B. He attempts to pasture his cattle on the land. B is privileged to use such force as is reasonable to prevent A from so doing.
2. A, as a joke, forges the signature of B, the owner of meadow land, giving C permission to pasture his cattle on the land. C attempts to do so. B is privileged to use such force as is reasonable to prevent C from so doing.
3. A receives permission from B to pasture his cattle upon meadow land which A and B both reasonably, but mistakenly, believe to belong to B. The pasture land belongs to and is in the possession of C. C is privileged to use such force as is reasonable to prevent A from pasturing his cattle upon C's land.
4. A constructs a dam which backs the water of a stream upon land which B reasonably, but mistakenly, believes to belong to him. B attempts to enter A's land for the purpose of removing so much of the dam as causes the backing up of the water. A is privileged to use such force as is reasonable and necessary to prevent B's entry upon his land.
b. Mistake intentionally induced by possessor. If the possessor of land or chattels intentionally causes another mistakenly to believe that he is entitled or privileged to enter upon the land or use the chattel, the possessor is not privileged to use any force to prevent or terminate the other's entry or use, until he has corrected the other's mistake.