"Uh, I'm happy that my father spanked me."
My father spanked me, too, and I was in no way harmed by that. He did not, however, use a whip on me. This is about "The Rod," not spanking.
No, this is about spanking, too. The author of this article is talking about "the Rod" but also about spanking.
Would I use something like this device? Probably not. And it probably does cross my personal line of what's appropriate. But I also think it's incredibly dangerous to mandate what the exact line should be, so long as a parent isn't clearly abusing their child. It foolish to try to set a "one size fits all" policy toward raising children because discipling a child is a lot like the old George Carlin routine about driving (anyone who drives faster than you is a maniac and anyone who drives slower than you is a moron). Anyone who disciplines a child more than you would will seem like the are abusing their child and anyone who disciplines their child less than you would will seem like they are being too soft. That's why I think we need to leave this up to individual parents.
Does this device go further than I would? Yes. Can I see good parents using something like this and raising good kids? Yes. Just because it might be abused it no reason to ban it. Apply your own gun control analogy as necessary.