Abstract: A marker system includes an enclosure with a controller therewithin. Emitters are electrically interfaced to the controller and include visible wavelength emitters and infrared wavelength emitters. The controller is configured to selectively initiate a flow of electric current though the visible wavelength emitters or through the infrared wavelength emitters causing the visible wavelength emitters or the infrared wavelength emitters to emit light and the light passes through the enclosure. There is at least one infrared detector, each of which is electrically interfaced to the controller and each of which is configured to detect infrared light that enters the enclosure. When the controller receives an electrical signal from any of the at least one infrared detector indicating reception of infrared light, the controller emits a signal to warn of the reception of infrared light (e.g., an audible signal, a vibration, a wireless signal, a wired signal).