Compliance with the provisions of this article shall not itself authorize any person to carry a concealed weapon or exercise any powers of a conservator of the peace. A registered armed security officer of a private security services business while at a location which the business is contracted to protect shall have the power to effect an arrest for an offense occurring (i) in his presence on such premises or (ii) in the presence of a merchant, agent, or employee of the merchant the private security business has contracted to protect, if the merchant, agent, or employee had probable cause to believe that the person arrested had shoplifted or committed willful concealment of goods as contemplated by § 18.2-106. For the purposes of § 19.2-74, a registered armed security officer of a private security services business shall be considered an arresting officer.