You want her thinking she is going to run all the way to the end EVERY Time. That way when you ask for the stop she will be thinking run. Which is what you want. To get a good stop you need to keep building speed all the way to the stop.
Yes. My trained fences her all the time, and I fence but not as much. I think she's learned that more often than not I'm going to stop before the fence. She has both of us figured - Because now that I think about it, I've never seen her stop early with Toni on her back.