Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 33, § 99

Whoever, not being in the service of the armed forces of the United States or of the commonwealth, appears in public wearing the distinctive uniform of any branch of such service shall be punished by a fine of not more than $1,000 or by imprisonment for not more than 6 months or both. This section shall not apply to: (i) any person discharged from such service, for any cause other than the own unworthiness of the person, wearing a uniform to take part in any military or naval parade or on any occasion of ceremony; or (ii) any person in the service of the armed forces of the United States, discharged for any cause other than the own unworthiness of the person, wearing the uniform from the place of discharge to the home of the person. A person found to have violated this section may be arrested without a warrant by any officer qualified to serve criminal process; provided, however, that nothing in this section shall subject to penalty any action with respect to the wearing of uniforms of the armed forces of the United States which is authorized by federal law.