Toffee would never run off. She sticks very close to me and would come if called, always. When she was a puppy, I had a house on 5 acres. It was only fenced by the road--on the other side was a pond, on the other two sides woods.. but she had almost a five acre yard to play in. She never went far from me, though she would happily run HUGE circles around me with her soccer ball. But she's always listened to me very well.
One time she took off after a squirrel and actually CAUGHT it with her paw. I yelled her name and she stopped and turned. Poor squirrel ran like the dickens to safety! Point of that story.... even with distractions she is very good about listening to me.
She's never in any yard, fenced or otherwise, without constant supervision though.