Crazy story about the electronic yard barriers. My dad had a pair of labs given to him when they were around a year old, a male and a female(fixed). Got them out to his place, opened the car door and .... gone! After hollering and b!t*hing at them for an hour or so, they came strolling back into the yard like nothing happened. Took them inside, only to let them out later and ... gone! The second time he yelled for about 5 minutes, then jumped in the car and headed to town. When he returned, the dogs were sitting on the porch. First thing he does is put the batteries in the collars and get them on the dogs. We proceed to bury the wire(this was back when the wireless setups were like $800), flag the perimeter, and plug in the power. Those dogs never left the yard again! Many years later, the male became a victim of the bad Chinese dog food fiasco. About 2 years after he passed, the female went blind from diabetes(but was otherwise healthy), so my dad did not put her down. Even blind, she knew exactly where to stop before the wire triggered the collar, and the wire hadn't even been "hot" since a year before the male died! Neither of them had a clue it was off, but they never tested the fence after the first couple days! Stayed waaaayyyyy back from the flags from then on, even long after the flags were removed.;):)