USPS OIG: How Do Employees Absent Without Leave Affect the Postal Service?
"Employees who fail to report for duty on scheduled days are considered absent without leave (AWOL), except when emergencies prevent them from obtaining permission in advance. An employee who is absent without permission or who fails to provide satisfactory evidence that an actual emergency existed will be placed in a non-pay status for the period of the absence. The absence may be the basis for disciplinary action."