Section 5. Any person residing in the commonwealth shall have the right to become a subscriber of a dental service corporation if his qualifications meet those specified in the by-laws of such corporation, provided that such a corporation may, in its discretion, refuse to issue a subscription certificate to, or upon due notice cancel the subscription certificate of, any person who has made any fraudulent claim or representation to the corporation or to a participating dentist, or has been guilty of uncooperative or unethical dealings with the corporation, or has failed to pay premiums and assessments seasonably and promptly or for any other cause which may be approved by the commissioner.