Section 94G. The attorney in fact shall execute no insurance contract with any subscriber unless the subscriber shall have agreed that, except as hereinafter provided, in case the funds on hand are not sufficient to meet the losses, he will, upon demand, pay to the attorney in fact an amount at least equal to and in addition to the current annual premium deposit called for by his contract, which liability shall endure as long as there are outstanding any claims on contracts issued while he was a subscriber. The total amount of the contingent liability of the subscriber shall be plainly and legibly stated upon each policy. Any domestic exchange meeting the financial requirements imposed on mutual companies transacting the same classes of business under section eighty-five A and section ninety-three F and which has made the deposit with the state treasurer required thereunder, may issue non-assessable policies. Any foreign exchange meeting the financial requirements imposed on foreign mutual companies transacting the same classes of business under section one hundred and fifty-two A may issue non-assessable policies. The provisions of this section relating to contingent liability of subscribers shall not apply to any such non-assessable policies.