In my country the cashiers will place the divider beforehand if you forget to do it and while the current customer is paying... So yes, the divider is for the cashier not for the customers.
General rules:
Exceptions may be made at the discretion of the mods.
In my country the cashiers will place the divider beforehand if you forget to do it and while the current customer is paying... So yes, the divider is for the cashier not for the customers.