It’s an engineering cost decision. I imagine they get single figure numbers of people making this change each year. The cost of having a developer design and implement a system to catch it, reject the change but save it in a state where it can be applied later, and automatically open either a support ticket or have an automated resolution system is far too high. Much easer to just lock the account and ask the customer to get in touch.
(Assuming there is a save button on the screen and it’s not an auto save on an input change, in which case yes it needs a confirmation dialog)
(Assuming there is a save button on the screen and it’s not an auto save on an input change, in which case yes it needs a confirmation dialog)