1. A method of selectively associating a person with one of a set of enrolled individuals who is to be tracked for participating in a multi-participant activity, comprising: executing a computer based application using a computing system, the computer based application tracking movements of one or more individuals determined by the application to be currently participating in the multi-participant activity, the tracked individuals being included in the set of enrolled individuals, where the tracked individuals are each physically in a system-sensed portion of physical real-world space, wherein the computing system previously identified the tracked individuals by using a sensor system having corresponding sensors in the system-sensed portion of the physical real-world space, the previous identifying of the tracked individuals being based at least on having detected one or more physical features of each of the enrolled individuals and on having generated and having stored, for each of the enrolled individuals, one or more visual signatures corresponding to the detected one or more physical features; using the sensor system and the computing system to automatically determine that an additional, not currently tracked person is being detected in the physical real-world space; using the sensor system and the computing system to automatically detect one or more physical features of the additional person, to automatically generate one or more visual signatures corresponding to the detected one or more physical features of the additional person, to automatically determine whether the additional person is a specific one of the set of enrolled individuals based at least on comparing the one or more visual signatures corresponding to the detected one or more physical features of the additional person to at least one of the stored visual signatures of the set of enrolled individuals; responsive to the at least one stored visual signature corresponding to the detected one or more physical features of the additional person satisfying one or more predetermined matching thresholds for the stored visual signatures mapping the additional person to the specific one of the set of enrolled individuals; and responsive at least to the mapping of the additional persona, tracking the additional person using at least the sensor system and the computer based application.