To limit the probability that the automatic compensating valve will increase water flow to a rate that exceeds that of the shower head it serves, which could lead to a sudden pressure drop in the hot or cold water delivery lines when other water-using devices are activated, which could lead to a sudden change in delivery temperature of the water, which could lead the user to abruptly move away from the shower stream, which could lead to an injury or fall, which could lead to harm to persons.