Section 28. If the employee is injured by reason of the serious and wilful misconduct of an employer or of any person regularly intrusted with and exercising the powers of superintendence, the amounts of compensation hereinafter provided shall be doubled. In case the employer is insured, he shall repay to the insurer the extra compensation paid to the employee. If a claim is made under this section, and the employer is insured, the employer may appear and defend against such claim only. The employment of any minor, known to be such, in violation of any provision of sections sixty to seventy-four, inclusive, or of section one hundred and four of chapter one hundred and forty-nine shall constitute serious and wilful misconduct under this section.
As used in this section the term ''minor'' shall include mentally retarded persons eighteen years of age or older unless:
(1) the employment takes place in a sheltered workshop which holds either a license from the department of developmental services or accreditation from the commission on accreditation of rehabilitation facilities; and
(2) a professional vocational specialist evaluates the employee at the employment site, for the specific job performed and such evaluation determines in writing that the employee is appropriate for and capable of such employment; and
(3) the employee has agreed in writing to the written rehabilitation plan or to an accurate verbal description of such written plan.
The division of administration shall keep statistical records on injuries that occur at sheltered workshops. If there appears to be a pattern of such injuries at a particular sheltered workshop, the office of claims administration shall notify the department of developmental services and such department shall take whatever action it deems appropriate.