I appreciate the question.
I'll use this example. At our feedlot, we bring a lot of western calves out of western Canada into Ontario. They have to stop at Thunder Bay for feed, water and rest. A situation arises where you load cattle in Saskatchewan, you're coming across and you figure on getting to Thunder Bay in time for your feed, water and rest. If your hours of service run out and you're two hours from Thunder Bay, there is no place there to unload in the middle of nowhere. You have to have the facilities to properly unload the cattle and reload them without injury or any undue stress to the animals.
In that situation, the driver would continue on and get those cattle to Thunder Bay, but he would be outside of his driver time.