When the bill is fully paid upon checkout, the bill can be automatically closed, when the receptionist clicks "check out".

Otherwise we get the following error: "To enable check-out, make sure that all bills are paid and the Unpaid items / Deposits section is empty. If there are any open items, convert them to a bill and then close it." on fully PAID bills, and to "bypass" that error, we just close the bill, without posting anything. Or some receptionists just move everything to a new bill, once again without posting anything, and only then they can check out the guest.

But it seem unnecessary, it slows us down, slows down training and confuses staff.

Otherwise, those are additional steps in an environment where you have queues... and it's very important for staff to check out people when they leave, to not slow down for example housekeeping (the faster they know when the rooms are empty the better, as otherwise they will wait till check out time, delaying the start of their cleaning, and knock on the doors to check if the room is empty). Time and money (wages) waste.

In general, if you want people to do something, make it easy... hence this request.