A large, fast-food chain unveiled a new touch screen register for its franchises. Each cashier was assigned a user id and password combination to log in to the register. The system allowed the incorrect password to be entered four (4) times before the register would lock and require a manager to unlock it with a key card. To prevent unauthorized access, the registers would lock after three (3) minutes if the screen was not touched. When the register locked, only the cashier who was logged in prior to it locking could unlock it without a system restart.
After a few days in operation, restaurant managers started complaining about the amount of time they were spending unlocking the registers. Some cashiers were forgetting their user Id and password, so other cashiers would log in for them. It also seemed that the button layout made it easy for the cashiers to key in the incorrect password. The managers also complained that cashiers would leave for a break or end their shift and forget to log out of the locked register. The managers would have to reboot the system, a three to five (3-5) minute process in order for the next cashier to log in. Additionally, managers noticed that grease was building up on the touch screens, making them less responsive.