@youngandtired:
My underground fencing is very good, she will not go over it b/c I have trained her not to. If she did she would probably be dead, lots of cars go by and she chases them just shy of the fence. If she goes close the collar device will give off a beep. When we are playing fetch outside and I throw the ball and it goes near the fence line she will stay put. She looks at me as if to say, "Go get it Mommy, I'm not. It has been great for us, I work and so does my hubby, and Sahara loves to be outside when the sun is shinning.
Just an interesting related story…not a commentary. A client of mine has a dog that is very nicely trained to their underground fence. They had had it for a few months, and the dog had never attempted to cross it. But one night, it snowed over a foot, covered the flags. The dog went right through it, and took the shock! The "context" of the fence changed for her when the terrain looked different. Luckily, after the snow left, she hasn't tried to cross the fence again.