The Problem:

The point of sale module assumes a cashier will always open the day with the previous closing cash and as such sets the opening cash as the previous session closing cash. Although this can always be changed manually, Cashiers typically forget to change the value which eventually leads to accounting issues, especially with the profit/loss statement.

The Solution:

In some business cases, it will be more rational to set the default to zero and have the cashiers change the figures when necessary.