It doesn't take a rocket scientist. Gravity is pulling down, the clamps are only holding via very strong friction and metal will expand or contract in different temperatures (although it's unlikely to change much indoors). Add any form of support from below and it will become as strong and reliable as you could ever want. Don't add any form of support and someday, in the middle of the dark night, you're going to slide and potentially launch yourself into floor headfirst if you're not careful.

Murphy's Law - Anything that can go wrong will go wrong.