A provision in an insurance policy that precludes the insurer from disputing the validity of the policy on the basis of
fraud or
mistake after a specified period. If the insurer wishes to contest the policy on any grounds that would justify
rescission of it, it must do so within the prescribed period, either by suing to cancel the policy or by asserting fraud or misrepresentation as a defense in an action instituted by the policyholder or beneficiary. 237 P. 2d 510, 512. The purpose of the clause is to require the insurer to investigate the accuracy of the information provided by the policyholder with reasonable promptness. It prevents the insurer from lulling the policyholder into a sense of security during the time when facts could best be ascertained, only to litigate them belatedly. Couch, Cyclopedia of Insurance Law §72.1 (3d ed.
1995).