Maryland Code, Insurance § 16-216

(1) 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;

(2) 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

(3) 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.

(1) the insured has received institutional, hospital, medical, or surgical treatment or attention within 2 years before the policy was issued; and

(2) 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.