That has happened in the past. Breakdowns at Conestoga or Sofina have happened and trucks have been lined up, waiting to unload. It's 30°C outside. The animals are getting warm. Everybody knows that they need ventilation. They ask that the trucks leave the site and drive, go out on the highway, get some air flowing through them for, possibly, half an hour and then return to the plant. That adds more driving time to their already tight schedule that day.
They get back to the plant—and, hopefully, things are running again—and get unloaded. It's possible that the driver's time could have expired in the meantime. When that happens, generally the driver is not allowed to park at the plant and needs to leave. It can happen that he needs to exceed his hours of service when he leaves the plant at that point.