The instrument termed a release is a contract that clearly portrays a meeting of the minds. It explicitly states a release from liability for known, unknown, present, and future injuries. In attempting to avoid such a release the party ordinarily may allege the grounds he may have under the law of contracts. In personal injury releases, these grounds usually take the form of charges of fraud or misrepresentation, coercion, inequitable circumstances, mutual mistake of law, unilateral mistake of fact, inadequate consideration, or mutual mistake of fact. We shall deal here with the defense of mutual mistake.
Avoidance of Personal Injury Release for Mutual Mistake of Fact, 7 Clev.-Marshall L. Rev. 98 (1958)