Mo. Rev. Stat. § 577.800: Unlawful use of unmanned aircraft over open-air facility or critical infrastructure facility, offense of — permissible acts — violation, penalty — signage — inapplicability, when.

1. A person commits the offense of unlawful use of unmanned aircraft over an open-air facility or critical infrastructure facility if he or she purposely:

(1) Operates an unmanned aircraft within a vertical distance of four hundred feet from the ground and within the property line of an open-air facility;

(2) Uses an unmanned aircraft with the purpose of delivering to a person within an open-air facility any object described in subdivision (1) or (2) of subsection 4 of this section;

(3) Uses an unmanned aircraft within the boundary of any critical infrastructure facility; or

(4) Operates an unmanned aircraft within a vertical distance of four hundred feet from the ground and within the property line of a critical infrastructure facility in furtherance of any violation of criminal law.

2. For purposes of this section, "open-air facility" shall mean any sports, theater, music, performing arts, or other entertainment facility with a capacity of five hundred people or more and not completely enclosed by a roof or other structure. For purposes of this section, "critical infrastructure facility" shall have the same meaning as section 569.086.

3. The provisions of this section shall not prohibit the operation of an unmanned aircraft by:

(1) An employee, owner, or operator of an open-air facility or critical infrastructure facility for the purpose of monitoring, inspecting, operating, or maintaining the facility;

(2) A person who has written consent from the president or chief executive officer of the open-air facility or critical infrastructure facility;

(3) An employee of a law enforcement agency, fire department, or emergency medical service in the exercise of official duties;

(4) A government official or employee in the exercise of official duties;

(5) A public utility or a rural electric cooperative if:

(a) The unmanned aircraft is used for the purpose of inspecting, repairing, or maintaining utility transmission or distribution lines or other utility equipment or infrastructure;

(b) The utility or cooperative notifies the open-air facility or critical infrastructure facility before flying the unmanned aircraft, except during an emergency; and

(c) The person operating the unmanned aircraft does not physically enter the prohibited space without an escort provided by the open-air facility or critical infrastructure facility; or

(6) An employee of a railroad in the exercise of official duties on any land owned or operated by a railroad corporation regulated by the Federal Railroad Administration.

4. The offense of unlawful use of unmanned aircraft over an open-air facility or critical infrastructure facility shall be punishable as an infraction unless the person uses an unmanned aircraft for:

(1) Delivering a gun, knife, weapon, or other article, including any explosive device or material, that may be used in such manner to endanger the life of an employee or guest at an open-air facility or critical infrastructure facility, in which case the offense is a class B felony; or

(2) Delivering a controlled substance, as that term is defined under section 195.010, in which case the offense is a class D felony.

5. Each open-air facility or critical infrastructure facility shall post a sign warning of the provisions of this section. The sign shall be at least eleven inches by fourteen inches and posted in a conspicuous place.

6. This section shall not apply to an operator of an unmanned aircraft that is being used for a commercial purpose that is otherwise operating lawfully, provided the operator is authorized by the Federal Aviation Administration to conduct lawful operations in that airspace.