All employers have employees who handle cash.
Any such person may find shortfalls at the end of the day. Other deficits, of all sorts may also arise, in many different ways. The employer may wish to discourage, or even penalise such mistakes, or simply to recover a sum he considers due to himself, by threatening to deduct such deficits from salaries. To employees this can seem unfair and harsh. The deficit may arise accidentally, or through any one of many ways where they are not at fault.