Md. Code, Bus. Reg. § 12.5-103

The provisions of this title may not be construed to prohibit the following: (1) bona fide sales demonstrations to locksmiths or locksmith suppliers by sales representatives who are not licensed; (2) emergency opening services by members of police departments, fire departments, or other government agencies in their official line of duty in order to protect against loss of life or property; (3) the acquisition, making, or use of any key duplication or key blanks; (4) the replacing of a removable or interchangeable core or recombinating a cylinder in a lock that was specifically designed by the manufacturer to be changed by the end user by use of a key; (5) the installation, repair, replacement, or rebuilding of a lock by the manufacturer of the lock; (6) the installation, repair, replacement, or rebuilding of an automotive lock by an automotive repair and service facility, the lock manufacturer, or the manufacturer’s agent; (7) the installation of locks by building trades personnel on projects that require a building permit; (8) the installation or replacement of locks by a retailer or the retailer’s agent: (i) on the premises of the retailer; or (ii) off the premises of the retailer if the installation or replacement of locks is incidental to the retailer’s normal course of business; (9) the installation or replacement of locks by a security systems technician who is licensed under Title 18 of the Business Occupations and Professions Article; and (10) the installation, repair, replacement, rekeying, or adjusting of locks or lock components for property by an employee or agent of the property owner or a management company.