Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 161, § 113A

Whoever fraudulently attempts to, or does enter upon or leave any vehicle or station of the Massachusetts Bay Transportation Authority by using a stolen employee or prepaid pass or a counterfeit employee or prepaid pass of said authority shall be punished by a fine of not less than one hundred nor more than one thousand dollars or by imprisonment for not more than one year, or both. Whoever attempts to, or does enter or leave a Massachusetts Bay Transportation Authority station or vehicle in the aforesaid manner may, if such offense is committed in the presence of a police officer, including a Massachusetts Bay Transportation Authority police officer or railway police officer, be arrested without a warrant.