That's why there's a choice of over 30 channels so people don't interfere with each other. During practice they use frequency clips, if anybody has that clip you know that channel is being used so you don't turn your stuff on and interfere with them. During the races everybody's frequencies are entered into the computer and it makes sure there aren't any conflicts in the races, if there are somebody has to go to an alternate frequency. At most big races like the nationals, it is required to have at least 3 different frequencies so there won't ever be conflicts in the races.