Section 64A. In any hearing by a licensing authority under the first paragraph of section 64 where a licensing authority finds that a licensee under section 12 has served or sold alcohol or alcoholic beverages either to a person under 21 years of age in violation of section 64 or to an intoxicated person in violation of section 69 within the 24 months immediately preceding the date of the alleged violation that is the subject of the hearing, the licensing authority may require, in addition to imposing any other sanctions, as a condition precedent to any modification, reinstatement or renewal of the license that the licensee provide a certificate of insurance for liquor liability providing security for the liability of the licensee to a limit of not less than $100,000 to any 1 person and $200,000 to all persons; provided, however, if the licensee is required to obtain insurance coverage under said section 12, then the licensing authority may increase the limits set by said section 12. Limits imposed or increased under this section shall be set at the discretion of the licensing authorities.