Subject to subsection (b) of this section, a policy of life insurance may not contain: a provision that the insurer may reduce or deny liability under the policy because the insured has previously obtained other insurance from the same insurer; a provision that gives the insurer the right to declare the policy void because the insured has had a disease or ailment, whether specified or not, or has received institutional, hospital, medical, or surgical treatment or attention; or a provision that gives the insurer the right to declare the policy void because the insured has been rejected for insurance, unless the right is conditioned on a showing by the insurer that knowledge of the rejection would have led to a refusal by the insurer to issue the policy. Subsection (a)(2) of this section does not prohibit a policy provision that gives the insurer the right to declare the policy void if: the insured has received institutional, hospital, medical, or surgical treatment or attention within 2 years before the policy was issued; and the insured or a claimant under the policy fails to show that the condition occasioning the treatment or attention was not serious or was not material to the risk.