A good use case for the "rule of 3": >if a certain event did not occur in a sample with n subjects, the interval from 0 to 3/n is a 95% confidence interval for

A good use case for the "rule of 3": >if a certain event did not occur in a sample with n subjects, the interval from 0 to 3/n is a 95% confidence interval for the rate of occurrences in the population.