The product is named after the swimming pool game where the player that is “it” closes their eyes and yells “Marco”, all of the other players are obligated to yell “Polo” in response. The player that is “it” follows the sound to tag another player who then becomes “it”.
Imagine that you could call your dog’s name really loud, so loud in fact that your pet could hear you calling up to 2-miles away and would then respond with an equally loud “woof-woof”. You could then follow the direction of the sound and know when you are getting close as the return bark got louder and louder. This is exactly what Marco Polo does, only using radio signals instead of sound.