Invisible Fence...  

Does anyone use or know someone who has an "Invisible Fence" for their dog?

I just want to say, though it's a convenient little tool, it's cruel. My parents got one for their dog and when she first crossed that line and was zapped, I think that is one of the most horrible sounds I've ever heard! She was terrified and, clearly, in pain.

Though now, a month or so later, she has gotten the hang of it. She can run around the yard on her own and she knows where not to go. She chased off some deer one day and stopped at the end of the yard. The little beeping before being zapped reminds her where she can't go, yet it still seems only a beep or two away from a painful experience. I wish there was at least a couple feet from the line before the pain came...

So I'm just wondering, anyone else one? Have you considered it?