I have to disagree with the notion that for it to be a race, or for someone to be a racer, that it must involve numbers and licenses. That may make it a sanctioned event by some governing body and in the eyes of those involved in those events it may make it more serious business, but that isn't necessary for a race to happen or for people to take the competition seriously. For example, many alley cat races are informal and set up by the participants.