 They are also used in airports and other controlled areas, where people are held until they clear customs or quarantine stations.Exit control locks are also used in libraries, where there is one well-staffed entrance and exit, and a number of other exits that are intended for emergency use only.Exit control devices are often used in hospitals, and can be interfaced to wireless sensors worn by newborn children, so that all exits will lock if a baby is stolen from one of the hospital rooms.