"I've had the opportunity to install and support a few different makes/models of cellphone charging lockers. 1) One of the biggest frustrations for supporting the lockers is the frequency with which people break the charging tips...With more people switching to USB C equipped devices  hopefully the breakage will decrease, I have tried bulk cheap cables even premium rugged cables and it seems like it does not matter in the slightest .2) People not shutting the doors properly, the main locker model  I support will not start charging until the door is fully closed and the LED in the compartment will then change from Green to red to show that it is occupied, I have witness people plugging in and walking off .....3) "forgot" my code you end up having to develop a security protocol to retrieve peoples phones if they get locked out. Lucky the machine has two ways to override both via the built in computer or manually opening the back of the machine and unlatching the lock should power get lost . The biggest gripe I have is that not all machines are super modular so if the power supply/control board for a locker fails you have to replace a board that has outputs for 5+ lockers"