If you're at all interested in the history of the samurai, or if you simply realize that Katanas Are Just Better, then check out this young man's blog post:
Samurai Zack: The Japanese katana is not a play thing, children!
He's not talking just about safety, but also from the perspective that the katana was a weapon revered by the samurai and treasured by the Japanese even today. So, testing one by trying to slice a metal folding chair (!) with it or by standing on it (!!) is disrespectful, plain and simple. Not to mention stupid.