That's also the contingency plan for the national postal service in Brazil (ECT/Correios) - a state-owned company. My father, an instructor, had to drive a van around the town to deliver express packages during strikes. The strangest thing about these situations was that old employees (a few were 80+) were also assigned to package delivery duties and some of them would end up getting lost. This was before cellphones were widespread, so Dad and his colleagues would go searching for the missing employees after lunchtime and bring them back to the office.
