Md. Code, Pub. Safety § 3-503

(a) The purpose of this section is to preserve, promote, and protect public safety and peace in the State. (b) This section applies to an agent, employee, or representative of another state or a political subdivision of another state who is present in this State to enforce the laws of the other state. (c) (1) A person subject to this section shall register with the law enforcement agency designated by the governing body of a county when the person enters the county for the purpose of surveillance of the presence or activities of customers or patrons of a business establishment in the State that is engaged in the lawful sale or supply of goods or services. (2) When registering, a person subject to this section shall provide: (i) the name and address of the person; (ii) the name of the person’s employer or principal; and (iii) the location of the proposed surveillance. (3) On request, the registration record shall be made available during normal business hours to the public and to lawful business or commercial enterprises in the State. (d) (1) A person who fails to register in accordance with this section may not register for 6 months after the failure to register is judicially determined. (2) The registration of a person who violates this section shall be suspended for 6 months after the violation is judicially determined. (e) A person who violates this section while the person’s right to register is suspended or while the person’s registration is suspended, is guilty of a misdemeanor and on conviction is subject to imprisonment not exceeding 2 years or a fine not exceeding $1,000 or both.