No policy of industrial insurance shall contain any of the following provisions:

1. A provision by which the insurer may deny liability under the policy for the reason that the insured has previously obtained other insurance from the same insurer.

2. A provision giving the insurer the right to declare the policy void because the insured has had any disease or ailment, whether specified or not, or because the insured has received institutional, hospital, medical or surgical treatment or attention, except a provision which gives the insurer the right to declare the policy void if the insured has, within two years prior to the issuance of the policy, received institutional, hospital, medical or surgical treatment or attention and if the insured or claimant under the policy fails to show that the condition occasioning such treatment or attention was not of a serious nature or was not material to the risk.

3. A provision giving the insurer the right to declare the policy void because the insured has been rejected for insurance, unless such right is conditioned upon a showing by the insurer that knowledge of the rejection would have led to a refusal by the insured to make the contract.